Chapter 3:

Production of Bioethanol from Sugar:

Source: Bioconversion of Sugarcane Biomass into Ethanol: An Overview about Composition, Pretreatment Methods, Detoxification of Hydrolysates, Enzymatic Saccharification, and Ethanol Fermentation, 2012 Larissa Canilha et al.

Figure: sugarcane overall composition

Source: Sugarcane energy use: accounting of feedstock energy considering current agro-industrial trends and their feasibility, 2013

Sugarcane cultivation remains, which refer to the solid residue from ethanol manufacture and sugarcane waste. Sugarcane bagasse is a fibrous remaining that evaporates after sugar juice is recovered by extracting and crushing process.

Production of ethanol using sugar raw materials:

Sugar cane, sugar beet, and sweet sorghum are sugar produce used as feedstock for ethanol production. Its main lubricants are high yields of sugar cane and conversion for low prices.

Country	Brazil
Costs	US$ 0.81 per gallon
Disadvantages	Natural seasonal availability
Total cultivated land	10%
Cultivated land for Sugar cane	13.8 million acres
Produce 4.2 BG of ethanol	7.4 million

Table: Ethanol production from sugar cane in Brazil in 2006

Brazil’s ethanol production is the cheapest in the world; witch costing US$ 0.81 per gallon without import levy. Where fiber is used in the stalks and leaves (bagasse) to produce process steam and electricity to the vital refinery. Liquid waste (Vinasse) is additionally used as fertilizer, processed within 24-72 hours of harvesting. Crushing the plant leg with specified rollers and let the juice release initially isolates the sugar, then the lime (calcium hydroxide) is added to sediment the sludge and fiber. Followed by the mixture is filtered.

Source: Sugarcane Biotechnology: Challenges and Prospects edited by Chakravarthi Mohan, Springer, Aug 9, 2017

Sugarcan, Saccharum, is a plant related to the poaceae group of family and category Monocotyledones. The key features of this family are the height is like flowers, internode stalk, and leaves with silica flacks on the border and open sheath. It can adapt easily in tropical and subtropical wheatear conditions. The most profitable part of cane sugar is the trunk where it accumulates a high amount of sucrose, which is used to produce sugar and its products, due to its high economic value, improved sugarcane varieties are more important to meet the needs required.

Source: Biomass to Biofuels: Strategies for Global Industries edited by Alain A. Vertes, Nasib Qureshi, Hideaki Yukawa, Hans P. Blaschek, 2011

Sugarcane

Sugarcane  Crush rollers

Juice heating

1st Lime additional and filtration

Sugar crystal centrifugal

Syrup A Molasses

2nd Lime addition and filtration

Sugar crystal centrifugation

Syrup B Molasses

Enzymatic saccharification

Yeast Fermentation

Distillation

Figure: Sugarcane bio refinery

Process description

The figure represents  (A molasses) is the remaining of liquid after the extraction of 77% sugar cane juice, raw saccharin during the first crystallization stage. Additional treatment of A molasses other extracts 12% of raw sugar to the production of  |B molasses which is used for the subsequent fermentation of ethanol. Invertase, which analyzes sucrose, is added to the yeast invertase dextran. Dextran inhibits the bacterial formation of dextran polymers that inhibit sugar recovery. In Brazil, hydro ethanol (5% water) resulting from distillation is used directly for fuel.The remainder solution after filtration is then evaporated to concentrate and help the sugar to crystallize, the former is to remove the coupling by centrifugation. High concentration syrup (blackstrap) B molasses that is used as a raw material for the following fermentation to produce ethanol after the no crystallized sugar and accompanying salts are intensified. In the procedure of fermentation of molasses is significant to use Heat Resistant Device, the yeast cerevisiae where they are large heat generation process in which estimates of 34-37 °C. When the temperature above 44 °C the manufacture of ethanol will reduce and increase the residual sugar content according to (Laluce et al., 2002). Usually, the molasses are contaminated by leuconostoc mesenteroides, which is a bacterium that leaches dextran chains of sucrose, which requires treatment-using dextranase.

Figure: sugar cane

Source: Engineering » Energy Engineering » “Biofuel’s Engineering Process Technology”, book edited by Marco Aurélio dos Santos Bernardes, ISBN 978-953-307-480-1, Published: under CC BY-NC-SA 3.0 license. © The Author(s) August 1, 2011

SUGAR CANE (SACCHARUM OFFICINARUM)

Sugarcane includes approximately from 12% to 17% of total sugar10% containing glucose and sucrose is 90 %. By grinding, it is possible to obtain 95% of sugar, and the remainder of it is a solid residue goes to what is called bagasse. The process of washing sugar cane is done in order to stir the initial cracking process before milling, and the juice of cane is treated in a balanced PH number. The yeast used in the fermentation process called Saccharomyces cerevisiae and then it is disposed of by centrifugation. The juice is warmed to more than 110 °C to decrease the threat of microorganisms contamination.

The extract then exits the fermenter to enter the distillation to extract the water from ethanol; it is called an isotropic mixture containing 95.5% v/v ethanol and 4.5% v/v water. It is then diluted using molecular strainers. The main objective of this process is to obtain a high concentration of ethanol without water. In addition to ethanol mixture, there is residue that is an aqueous solution exits the distillation procedure.

Figure: bioethanol production from sugarcane

Source: Continuous production of bioethanol from sugarcane bagasse and downstream purification using membrane integrated bioreactor, koel Saha, 2017

Materials used for treatment and hydrolysis

Sugar cane is gathered from the local juice mill and then cleaned using water and

subjected to precise drying processes. It is divided into small pieces and is grinding by (Bajaj Twister Mixer Grinder) and is sown with a dimension ranging from 250 μm – 500 μm.

Principal processing and sugar cane are subjected to enzymatic degradation:

Ionic pretreatment of sugar cane processing with the help of ions is performed in a temperature of 140 ° C and for approximately 120 minutes, the cellulose enzyme is used as an intermediary for the re-generation of cellulosic materials and their exposure to enzymatic hydrolysis Citrate buffer maintain the pH at 4.8. Hydrolysis is performed under conditions such as the temperature of 50 ° C and 150 RPM for 72 hours. When enzymatic decomposition is completed and sugar concentration is reduced, sugar is then exposed to fermentation.

Process fermentation:

After enzymatic hydrolysis of sugar was completed, hydrolysis was used to prepare the medium for the fermentation process. The concentration of sugar reduction was in the hydrolysate 48.4 g/l.

Equipment used in the experiment:

Using material, which has the ability to resist rust to manufacture A 20 l of laboratory-scale yeast. Using a water bath to maintain the temperature, where the temperature is maintained at 32 ° C and the pH measurement is provided using PH meter. The membrane units have been installed which are the MF membrane and AF membrane to monitor the transmembrane pressure.

To carry out nanofiltration in the situation of great transmembrane pressure using extreme pressure diaphragm pump. The NF unit has 5 l gathering container used to store the final production.

Figure: Diagram showing experimental equipment

The concentricity of the cell defines from standardization, which designed using the clean culture of Saccharomyces cerevisiae. The supernatant, which is a liquid lying above a solid residue after centrifugation process, is used to decrease analysis of sugar and ethanol. The concentration of sugar reduction is determined by DNS method that defines as a guessing the concentration of decreasing sugars in a tester.

Result Pretreatment with ionic liquid of ethanol production:

Pretreatment technology	Microorganism	Sugar concentration	Fermentation condition	Ethanol concentration	Ethanol Yield	Ethanol productivity
Ionic liquid  T= 140 °C t= 120 min	Saccharomyces cerevisiae	48.3 g/l	Batch fermentation t= 20 h  T= 32 °C 120 rpm	18.4 g/L	0.38 g ethanol/g	0.96

Source: Bioelectricity versus bioethanol from sugarcane bagasse: is it worth being flexible, Felipe F Furlan, 2013

Figure: Ethanol production in the first generation

Figure: Ethanol production in the second generation

Figure: Main characteristics for 1G+2G bio refinary ( BioEth)

Source: Bioethanol Production from Sugarcane Bagasse using Fermentation Process, Wong Y.C,2014

Material and methods:

Sugarcane Bagasse Preparation:

Sugar cane is well-washed using tap water and cut into small particles. The sugar cane is then dried at temperature 600 ° C for three days. This degree is very suitable, if the higher temperature may affect the sugarcane enzymes. After being dried, sugar cane was ground by a crushing engine and stored in room environments.

Buffer forming:

The buffer is used to dilute the enzyme, such as glucoamylase and alpha-amylase. The reaction of the enzyme is further effective if the buffer is diluted compared with purified H2O. There are two main categories of buffers which were phosphate buffer arranged for a-enzymes and for glucoamylase used sodium acetate buffer and acetic acid. After the buffer has been prepared using aluminum foil as a cover and keep it at room temperature for additional use.

Sugarcane liquefaction:

A quantity of 10 grams of sugarcane is weighed and the sample is placed in a conical flask and additional 200 ml distilled water to the taster. The PH was prepared using 0.5 ml of NaOH micro-liters of alpha-amylase enzymes are added to the mixture and the mixture is warmed. The temperature is 500 ° C. The alpha-amylase works to break the cellulose to smallest particles denotes dextrin.

Sugarcane bagasse saccharification:

The combination refrigerated to 400 ° C, then added a secondary enzyme which known as  (glucoamylase) to the combination. Before Glucoamylase added to the slurry must be dilute help with acetic acid and using a buffer, for example, sodium acetate. The mixture is kept at 500 ° C and glycolysis decomposes dextrin for fermentation of glucose. The mixture was cooled to 320 ° C and 10 mL saccharomyces were added to the sample before being moved to a blended flask.

Sugarcane fermentation:

During fermentation procedure, the method used to ferment the simple sugar into carbon dioxide and ethanol was Saccharomyces cerevisiae (baker yeast). To know the real influence of PH on ethanol income, the temperature was kept same at 37° C, while the PH was various from 3 to 5. On the other hand to define the influence of temperature on the final ethanol yield, the fermentation procedure continual for 48 hours and held the PH constant approximately 4.5.

Ethanol distillation:

Whatman filter paper was used to filtrate the sample after 48 hours, and to segregate the ethanol from the heavy material. The rotary evaporator was used to distillate the bioethanol and heated the sample at 80 ° C.

Determining the yield of bioethanol:

Bioethanol is analyzed as a high-performance liquid  (HPLC), and 20 μl of the taster was added to the same previous system to define the yield of bioethanol. The composition of fatty acid was examined in the virgin coconut oil using the HPLC technique. The subsequent situations used for the examined parameter of HPLC: column C18RP (53*7mm), temperatures used for injector was 30 ° C, the taster added to the HPLC was 20 μL.

Calibration curve:

The calibration arc was sketched to define the total concentration of ethanol in water from samples of sugarcane, where the diagram was drawn so that the ethanol ratio was 95% as standard, and then the standard was organized at diverse concentrations, for example, 25%, 50%, 75% and 100%.

Source: Bioenergy: Principles and Applications By Yebo Li,2016

Effect of pH on ethanol productivity:

It is possible that pH limits yeast progress by changing enzymatic activity, unit permeability and the accessibility of metal ions. It is possible that the yeasts have the ability to survive on a wide scale of pH (2-8), but the best growth rate is (4.5-5) and is considered as acidic.

It was observed that the fermentation period was longer at a lower pH and when the PH more than 5 during ethanol fermentation will effect to decrease the ethanol yield.

Temperature relationship with ethanol productivity:

Temperature variations affect progress amount, cell permeability, nutrient needs, metabolism, and enzyme action. S.cerevisiae can develop at a temperature of between 5 and 38 degrees Celsius, but fermentation regularly occurs at 30 degrees Celsius. To accelerate growth in the first phase, the temperature is adjusted and controlled at

35 ° C.

Source: Impact and significance of microbial contamination during fermentation for bioethanol production, Ramon Peres Brexó, 2017

Manufacture procedure of bioethanol from sugarcane:

1. The primary step of treatment is the cleaning and processing of feedstock’s to obtain juice with a high percentage of sucrose. This step is performed throughout cleaning using water or dry washing. It was noticed that cleaning with recycled water can be applied but may lead to damage of fermentable sugars from sugarcane to water and that this procedure also leads to improved bacterial contamination of sugarcane juice obtained for fermentation. Due to the constraints of washing the sugarcane using water, dry cleaning was used as a substitute for the previous process, by the mechanical elimination of the vegetable elements by applying the fans and splitting the mineral contaminants into particular benches with roles.

2. After cleaning procedure, sugarcane units are disrupted by adjustment (rotational knife), chippers (oscillating knife) to decrease element dimension and progress sucrose removal. It is possible to extracting sucrose by diffusion or compressing. One mill or several mills where the cells are broken by pressure do the grinding process. The sucrose diffusion occurs in the opposite flow of sugarcane with water at 70-80 ° C.

3. Once gained sugarcane juice, then sifting through the sieves rotary and fixed and add more limewater (calcium hydroxide, Ca(OH₂) and sulfur dioxide (SO₂).

4. Heating is important because it is based on the stimulation of erosion and deposition of impurities and also for the analysis of proteins and starch and to remove gas.

5. In the next step, sugarcane juice is poured to eliminate the organic and inorganic and colloids that have no fermentation ability. Adding sugar waste, sugarcane molasses modifies sugar content.

6. The manufacturing fermentation is divided into three diverse stages: preparation, which is considered a preliminary stage before fermentation, and pre-fermentation, it is complementary to the fermentation stage, Categorized by the lateness stage of yeasts units after their vaccination in a percentage of 20% v/v with sugarcane must.

7. The supplemental phase, which lasts for about 7 hours, is categorized by constant CO 2 excretion and gradual and stable reduction in heat. The fermented requirement named “wine” found a complicated arrangement of fluid, solid and vaporous ingredient and must cover minor quantities of sugars.

The best temperature for growing is 20 to 30 ° C and the pH of 3.2-6 and the great amount of osmotic tolerance. 10-20 % of sucrose, 0.3-0.5% ash, 78-86% water, 0.1-2% reducing sugar and 0.5-1.0-nitrogen compound. PH in the variety of 4.5-5.5 and the temperature between 26-35 °C and using lactic acid bacteria with 83 % of bioethanol production.

Source: A new approach for bioethanol production from sugarcane bagasse using hydrodynamic cavitation assisted-pretreatment and column reactors, Ruly Terán Hilaresa,⁎, 2018

Resources and procedures:

First and foremost, dehydrating the biomass followed by categorized and crushed throughout a normal filter of 2 ½ net and then keeps in a 16 net screen for running the experiment. For pretreatment of sugarcane bagasse was using Hydrodynamic cavitation (HC) technique, which depends on recirculation container and cavitation sector using liquid with a flow amount of 5m^3/h. procedure liquid temperature was kept at 60 °C throughout pretreatment and using water-jackets, also the ahead stream pressure was fixed to be 3 bar.

Hydrogen peroxide pretreatment tests were done with the help of HC technique. 20 grams of dehydrated SCB were used in the form of a tubular cable cloth and the design is used Benhken for possible changes when adding hydrogen peroxide and sodium hydroxide.

Under ideal situations, and also under the conditions without of H₂O₂ and NaOH to create statistics for evaluation. After processing, biomass was gathered, cleaned with purified water, dehydrated and lastly examined for lignin, cellulose, and hemicellulose. The tasters are then undergoing to treatment using hydrolysis enzymes, with a (pH 4.8). Yeast such as Scheffersomyces stipitis itis and Candida shehatae used for ethanol fermentation procedure. Ethanol production was expanded using HC method in the second generation, where a great revenue analysis of more than 95% was found even with light treatment situations and a short period of operation.

Source: Biomass to Biofuels: Strategies for Global Industries edited by Alain A. Vertes, Nasib Qureshi, Hideaki Yukawa, Hans P. Blaschek, 2011

Beet molasses is a by-product of the manufacture of sugar with sugar beets, as in reed molasses. This material is found during the crystallization and vaporization stages of the mass heated from the vacuum pans, and there is a small relationship in the installation of beet molasses with cane molasses.

The sugar beet considers as a major source of sugar in Europe and North America, also used in the process production of biofuels in France. Beet sugar is well harvested at about (25-50 tons per acre) and produces in temperate climates with less rainfall contrast with sugar cane because sugar cane is grown in rainfall areas. The production of ethanol from sugar beet needs chemical inputs and energy source and is therefore further expensive compared to the previous process that can use sugar cane.

Figure: sugar beets

Source: Engineering » Energy Engineering » “Biofuel’s Engineering Process Technology”, book edited by Marco Aurélio dos Santos Bernardes, ISBN 978-953-307-480-1, Published: August 1, 2011, under CC BY-NC-SA 3.0 license. © The Author(s).

Sugar Beet:

Sugar beet can be used to achieve bioethanol through distillation and fermenting its juice. Initially, the beet is cut into fluffy pieces and then located in a previously extracted solution such as juice or water and raised to a temperature of 70-80 °C. In the situation of sugar beets, the temperature must be high enough until the proteins are sufficiently shredded from the walls of the cells including the sugars.

After completion of this process, the sugarcane pulp is subjected to drying and selling as animal feed or in medicinal industries, and the process continues to produce bioethanol. Juice can be used both straightforwardly or can be concentrated in evaporators and kept for long periods. The process of fermentation depends on the use of yeast preferably Saccharomyces cerevisiae or bacteria, for instance, Zymomonas mobilis, only used for fermentation which is not continuous. High interest in bacteria is due to its ability to convert glucose to ethanol very efficiently compared to yeasts. Ethanol production from raw sugar beet pulp is estimated at 54.53 g / L.

Figure: Bioethanol production from sugar Beet

Figure: Bioethanol production using sugar beet

Bioethanol production process:

The raw material (beetroot) is cut into pieces (A) and the resulting solution (B) is gathered. In the following stage, mixtures containing minerals, organic compounds, and other sugars are extracted using water at 70-80 ° C for the production of several types of juices (C). The wet material is pressed automatically and the juice found (D) was mixed with those achieved before in the B and C. A mixture of B, C and D samples are treated with calcium hydroxide at a heat of 40 ° C and 75 ° C before CO2 is added to the solution. The key determination of the previous two stages is metal removal and metalloids Removal of raw materials by precipitation are unsolvable carbonates and hydroxides.

The cleansed juice is then heated. Once the water is partly vaporized in part (E), a new liming is created at 85 ° C and produce pure juice (F). In the following stages, the juice is warmed to produce a syrup with no>30% containing water and a great percentage of sugars G). Some crystallization procedures were used to gain sugars from this mixture and the remainder of the solution was gathered and centrifuged. In the end, distillation leads to the manufacture of final bioethanol (J). The remaining heavy materials of the distillation method were utilized as fertilizer (I).

During distillation, the metallic concentrations are reduced by a factor of 1000-10,000 to display efficient decontamination for the final production of bioethanol. The EU uses sugar beets to produce 30 % of bioethanol and 59.89 g / L for Sugar beet juice.

Source: Evaluation of the fermentation of high gravity thick sugar beet juice worts for efficient bioethanol production, Piotr Dzingan, 2013

Sugar beet is studied to be an attractive feedstock for manufacturing of ethanol because of its contented of fermented sugars. In a very detailed way, the handling of intermediate mixtures in ethanol is facilitated due to they do not need pre-treatment or enzymatic therapy compared with the production of ethanol using starch as a raw material.

Source: Biomass to Biofuels: Strategies for Global Industries edited by Alain A. Vertes, Nasib Qureshi, Hideaki Yukawa, Hans P. Blaschek, 2011

Sweet sorghum diversities are rare and not commonly grown, although some contain sweet corn, which means that sucrose content is high. In sweet sorghum, sugar is in the main stem and is recovered by pressure on stalks and growers (almost similar to the process used for sugar cane). China is seeking to convert from corn to sweet sorghum, as sorghum is more drought-tolerant and can grow in the desert regions of China. Agriculturalists can advance advantage in the use of sorghum grains since ethanol is generated from sweet juice sticks in the stalk. These services join new and stable technologies for ethanol, sugar, grains, and fiber. The greatest gainful option is a flexible facility that can help both sugar and fuel ethanol to the market based on their relative market prices. However, steady the use of bagasse between ethanol production and power generation display opportunities to advance engineering.

Figure: Sweet sorghum

Source: Evaluation of bioethanol production from juice and bagasse of some sweet sorghum varieties, Soha R.A.Khalil,2015

Sweet sorghum, which contains sugar-rich legs and water-use productivity, has a suitable possible as other raw material for ethanol as well as non-competition for human feed on the ground.

 Methods and Materials:

The study was conducted on five diversities of sweet sorghum (Sorghum bicolor, L.,

Moench), namely GK-Coba, Mn 1054, Ramada, Mn4508, and SS-301, which were found from the Sugar Crops Study Organization, where these crops were harvested and planted, and then the leg juice is removed at the farming study situation. Seeds start production in the first week and then are harvested after 120 days. For high-quality subject crops to the dough stage which is appropriate.

The yield of sweet sorghum diversities:

20 random samples of each type are collected and filtered to extract the stalk juice. Using three rolling mills, the stems extracted from the sweet corn are stripped. A clean cotton cloth pass to remove any large pieces of the suspended material then examines the raw juice.to calculate the Bagasse gross yield/fed using the following equation: Wet bagasse yield ton/fed =Stripped stalks yield ton/fed –juice yield ton/fed.

Sweet sorghum bagasse measurable examination

To calculate the moisture content of bagasse, where the amount of 5 g of fresh bagasse was taken, and dehydrated in the kiln at 105 ° C, till a constant value is got, followed by, the sample was cooled using a desiccator, finally determine the value of moisture.

  Pretreatment for Bagasse to produce bioethanol:

The aim of this research is to ensure more advance energy profit by manufacturing bioethanol from sorghum Bagasse of sweet sorghum. Bioethanol manufacture from the amount that remains after the main part Contain two prime steps, firstly bagasse pretreatment and secondly, fermentation of bioethanol manufacture. Pretreatment of bagasse depends on by diluted acid hydrolysis and regulate the PH at 5.5 -+ 0.2. The regulator treatment includes additional of 5 g of sweet sorghum bagasse to 250 ml Erlenmeyer bottle holding 95 ml of water and consist 98% of sulfuric acid in 95 mL of 2% (v/v) and keep the pH 6.7-+ 0.2. Hydrolysis is completed at 120 ° C for 60 minutes. The pretreated bagasse was filtrated and ensures that no hard element remains and neutralized the high sugar fluid.

Determination of total percentage of sugars in bagasse hydrolyze:

Firstly, an examination cylinder, 0.5 mL of hydrolyzing bagasse was blending with 1 ml of phenol mixture (2% w/v) and then 2.5 mL of sulfuric acid (98%) was added and remain in the dark For 10 minutes and then cooled to 25 ° C for 30 minutes. Absorption was measured using a spectrophotometer at 490 nm.

Method of producing bioethanol from sweet sorghum bagasse:

After the completion of the process-neutralized hydrolyzes, which is done with the juice, was treated for 20 minutes at 120 ° C. 95 mL of hydrolyzed acidic sterilized supplemented with nutrients, fertilized and incubated and then bioethanol is extracted.

Figure: manufacture of bioethanol from the juice of three chosen diversities of sweet sorghum

Figure: fragmented juice content of five varieties of sweet sorghum

Source: Engineering » Energy Engineering » “Biofuel’s Engineering Process Technology”, book edited by Marco Aurélio dos Santos Bernardes, ISBN 978-953-307-480-1, Published: August 1, 2011, under CC BY-NC-SA 3.0 license. © The Author(s).

Comparison of the several of raw materials:

The main factor that affects the production of ethanol is choosing the proper raw material because largely depend on the local weather situation. North America and Europe have relied on starch-containing materials to produce ethanol because they have special environmental and agricultural conditions, but these situations make it unsuitable to produce sugar cane, although this plant provides extreme ethanol yield. For example, energy crops in these areas usually grow in cereals form. The recorded yield per tone of raw materials is greater for beet sugar molasses compared with cereals, although the growing sugar is less productive than grain. The yearly manufacture of ethanol from beet is greater than that of cereals. It is critical that the geographical location of the crops is analyzed to help us determine the appropriate place for the plant in the appropriate environment.

The bioethanol yield per hectare is obviously relied on the crops applied and is estimated to average production in Europe referring to the crop category, which is presently predestined at 2790 liters/hectare, referring to 400 liters/ton and the average yield in seeds of 7 tons/hectare. Bioethanol can be positively created in temperature climate; high production yields can find it in the tropical climate. Sugar cane is used to get the production capacity of 6200 liters/hectare estimated in Brazil. This estimate based on the productivity of crops of and 90 liters/ton and 69 tons/hectare. In India, ethanol production is also great from sugarcane, where its productivity is estimated 5300 liters/hectare.

Ethanol production plant using Dry- Mill starch and Dry-Grind

Source: Biomass to Biofuels: Strategies for Global Industries edited by Alain A. Vertes, Nasib Qureshi, Hideaki Yukawa, Hans P. Blaschek, 2011

It is necessary to treat sorghum directly after it is harvested; it is more than carbohydrate in storage. More than 20% of the fermented plants in corn have a short growing season. The addition of ethanol production and the use of maize originated as feedstock, during the process called (saccharification).

Extra of more steps to the ethanol manufacture process, due to the starch polymer must initially be cracked down to the small pieces of sugars. Plants use one of three main approaches to the primary processing of corn grains:

1. A dry-grind process: comprise crushing the kernels in comparatively smooth powder.

2. A dry-milling process: which focuses on the different types of beads to series of roller mills, then check to detach the microbe, fiber, and endosperm.

3. A wet-milling process: Which contain the processing of beads with sulfuric acid to amplify them previous to the series of the milling process which contains split of the density and washing stages to separate the starch, protein, germ, and fiber.

Figure: Ethanol production by dry-milling process

After the separation process, the starch (a process of degradation called dextrin, which consists a smaller chain, water-soluble glycol polymers) is heated by adding water, alpha-amylase enzyme and detained the mixture at temperatures approximately 90-100 degrees for a period of 15 to 60 minutes, and in this way occurs the process of sugars, where the conversion of dextrin into sugars with the ability to ferment.

After the following procedure of saccharification, the yeast and nutrients are added and the combination is then initially fermented and then the distillation process is carried out. Followed by the ethanol leaving the distillation column to the molecular filter to ensure that there is no residual material and all water is removed. Furthermore, dry-mill/grind plants cost less compared to wet-mill ethanol plants. The yield from the last operation will progress extra value-added products mainly corn feed gluten and corn gluten meal.

Modified processing of conventional dry milling plants has been developed to import any no fermentable such as microorganisms, fat and fibrous parts, and the aim of this strategy is to increase the value, amount and the food composition of the company’s products.

During the dry grind process, the corn is push through the hammer mills, which convert big particles to subdivision particles to make water and enzymes easy to pass in the following procedure.

The best ethanol yield that will be attained during the process of around 2.85 gallons per bushel of mealies with atom range of roughly 0.6mm and crossing over 2 mm screen. The ground corn is heated between 85 and 140 ° C and slurried with water and with help of alpha-amylase enzyme, this procedure has two main reasons first, to crack cell wall that includes starch and to change the starch polymer to a soluble gummy substance, which contains a polymer, whose molecules consist of relatively few repeating units. When the temperature more than 100 ° C will improve hydration and contributes to the process of crystallization of the granules of starch and using the lactic acid microorganisms to decrease the contamination.

 Source: Energy Efficiency and Renewable Energy Handbook, Second Edition edited by D. Yogi Goswami, Frank Kreit, 2015

Figure: Dry grind corn to ethanol

There are four main process steps in dry-grind ethanol:

1-    Pretreatment

2-    Cooking

3-    Fermentation

4-    Distillation

During the pretreatment method, the corn kernel is grinded to very fine particle and then blended with water, ammonia, and enzyme. To make sure that no bacteria in the mixture or reduce the level of microorganism the whole mixture is cooked, and after refrigeration, the mixture is delivered to fermenter process and it stays for 40 h or further an alcoholic drink made from yeast-fermented malt flavored with hops which contain stillage and ethanol. To subdivide the water and stillage content from ethanol need sufficient energy-dense distillation in order to attain maximum concentrations around 95%, but in order to get 100% ethanol, the best way is to use a molecular sieve. The new plants are likely to produce more than 2.7 gals of ethanol per bushel of corn made. Usually dry mill/grind process is a batch process, which means that it can work uninterrupted if the various type of tanks are working and arranged so that log-phase progress happen in one tank, while another is manufacturing ethanol in the beer well under controlled temperature of around 60 ° C and the optimum corn growth under the PH (4.8-5).

Modified processing of conventional dry milling plants has been developed to import any no fermentable such as microorganisms, fat and fibrous parts, and the aim of this strategy is to increase the value, amount and the food composition of the company’s products.

During the dry grind process, the corn is push through the hammer mills, which convert big particles to subdivision particles to make water and enzymes easy to pass in the following procedure

Figure: Ethanol yield from various bio-renewable resources

Source: Advances in Bioethanol By Pratima Bajpai Springer Science & Business Media, Aug 30, 2013

 

Figure: Wet mill processes of ethanol production

In wet mill process the kernel that is part of a nut, seed, or fruit stone contained within its hard shell break down into the independent element, starch portion come from endosperm just input to the ethanol fermentation procedure. The wet fractionation method depends on the process of soaking until the nucleus is isolated and on the possibility of restoring the clean starch stream, corn kernels are hydrate by soaking where it is soaked in sulfuric acid with a range of about 0.12% to 0.20% at a temperature of 52 ° C for 24-48 h. The operation is performed all stages in a sequence of tanks by the process of rotating current, the purification process is monitored by adding sulfuric dioxide with water to the old corn close to the end of the soaking procedure

One of the uncontrolled features is that it is significant that the wet mill is the sharp growth process of the bacteria in the new corn holding tanks, where the concentration of sulfuric acid is lower, the bacteria, most of them are part of the lactic acid cluster of Gram-positive microorganisms that create lactic acid in acute reservoirs Early times. A mixture of lactic acid and sulfuric acid to make the kernels dilutes and causes them to expansion, dissolving the protein matrix results in starch release. There is a process have been developed to reduce concentration and time using enzymes such as a protease.

After the soaking process, the germ, fiber and gluten protein are separated from the starch. The segmentation process is a component of the nucleus and is the foundation for the extra products made in the mills. The germs are recycled depend on the density and treated to regain corn oil, and washed to eliminate any remaining starch, extracts germs and distillation columns. The resultant combination is corn gluten feed, which has a little in protein animal feed. The starch and gluten are unconnected using centrifugation principle. The starch stream is transferred to ethanol and gluten protein is dehydrated and sold as corn gluten meal. Gluten is a protein-rich poultry feed, and the acute liquid can be used as a fermenting component.

The process was divided into six important steps.

1. Grinding: Corn grains are ground into powder and flour.

2. Liquefaction:  add water to the cornmeal and the temperature rises in the mash to dissolve the starch.

3. saccharification: The enzymatic hydrolysis of starch release simple sugars, particularly glucose.

4. Fermentation: The fermentation of the starch hydrolyzes using yeast and converted to CO2, secondary metabolites and ethanol.

5. Distillation: where fermented beer or shower in 10% v/v ethanol is purified to -96% v / v ethanol with solid remainders converted to animal food.

6. Drying: The remaining water in the ethanol distillation process is removed by using molecular sieves to manufacture anhydrous ethanol. After cleaning the mealiest, biomass or other cereal where it first crosses through the hammer grinders that mill into a soft powder.

The mixture is mixed with water and the alpha-amylase enzyme; passing through the stoves starch becomes liquid.  A PH 7 is preserved by the addition of sodium hydroxide or sulfuric acid and also uses heat to allow liquefaction. High-temperature phase is used (120-150 ° C) and low temperature (95 ° C) is maintained. The aim of great temperatures to decrease the microorganisms in the mash. The glucoamlase enzyme is added to transfer starch particles to (dextrose) fermentable sugars.

Different chemical methods of pretreatment for cellulosic biomass

Cellulosic biomass has a diversity of physiochemical features and the primary need for pretreatment technologies to help the productivity of carbohydrate polymers into fermentable sugars.

It is essential to choose the suitable pretreatment methods because

1- difficult arrangement of lignin and hemicellulose

2- Effect on the sugar yields

3- Prevent the degradation of sugars derived from hemicellulose

4- Reduce the creation of inhibitors for following fermentation stages.

1.    Acid treatment:

In the acidic pretreatment, condensed acids are diluted by about 0.2 W/W% to 2.5 W / W % to biomass and continue to mix at 130 ° C to 210 ° C are in two special conditions. First, when the temperature is high in continuous-type for small solid loading, that is, above the 160 degrees Celsius. Second, in tough acid hydrolysis batch manner for great solid loading the temperature is less than 160 degrees Celsius, also from the place where they are singled out it is also possible to use strong concentrated acids such as HCL and H2SO4 exclusive of enzymatic hydrolysis where the reaction is carried out under moderate temperature situations from many diverse types of raw materials. In hydrolyzed hydrolysis, the structure of the material is broken followed by the elimination of hemicelluloses, which growths the enzymatic digestibility of biomass and porosity.

It is also possible to use organic salts in the treatment of diluted acid. The main benefit of this method is the great solubility of lignin and hemicellulose in acid with large revenue of glucose without resorting to the more enzymatic hydrolysis.

2. Alkaline treatment:

This process is carried out by immersion of the biomass in the alkaline solution, for example, calcium, potassium and sodium ammonium hydroxide and then mixed at a temperature suitable for a certain period of time through this process change the structure of the glucose and remove the partial crystallization of cellulose and the occurrence Molecular Decomposition Process hemicellulose

Neutralization method using to separate lignin from inhibitors.  This process needs fewer severe situations related to the other pretreatment approaches. Switchgrass, bagasse, corn stover, rice straw and Wheat revealed the result of this method. Using CO2 during the neutralization exclusive of the demand for solid-liquid split-up. Lime pretreatment considered as expense effective and require dense energy.  One of the advantages of this method is that the lignin structure is changed and removed effectively.

Source: Multi‑product biorefineries from lignocelluloses: a pathway to the revitalization of the sugar industry, Farzad S, 2017

Figure: Ethanol production

Pre-treatment for steam explosion Sulfur catalyst is used with along with simultaneous saccharification and co-fermentation (SScF). The ethanol manufactured up to 92.55% is cleaned by the distillation column and then dilute by the molecular filter column to meet the fuel-rich ethanol with 99.5% cleanliness. The evaporation element is not only used to clean the water sand for internal re-processing but also until the syrup is produced from the appropriate solubility for the common feeding of the boilers.

Source: Integrated versus stand-alone second-generation ethanol production from sugarcane bagasse and trash, Marina O.S.Dias, 2012

Simulations were established to exemplify diverse technical scenarios, which offered statistics for commercial and eco-friendly study.

The consequences displayed that the first and second generations of the procedure of ethanol manufacture integrated with sugarcane results in well financial outcomes likened with independent plants, particularly when incorporating progressive pentose’s fermentation and hydrolysis methods.

Source: Advances in Sugarcane Biorefinery: Technologies, Commercialization, Policy … edited by Anuj Chandel, Marcos Henrique Luciano Silveira, 2017

Some agronomic technologies and how to use them:

Soil mapping and the environment for sugar cane cultivation:

Cartographic systems were commonly used in Brazil sugar production in the late 1970s. Where the program was used proalcool to select an area to install alcohol distillation and sugar cane factories. These maps were resulting from soil charts manufactured by the National Center for Agricultural Research and Education.

With regard on this evidence, in 1992 the Center of Copersucar Technology (sugar cane technology center) obvious to start a study program specialized in studying the soil categories and their association with the yield of diverse types of sugarcane. Based on the 1994 results, a system called environments of creation for sugarcane harvests was introduced. Diverse soil sorts were classified into five categories depending on high and low yield.

The availability of a technological production environment needs to be further understood by agricultural engineers and technicians. Soil maps on an inadequate measure are regularly used to develop an environment of manufacture used in the development of specified planting strategies for agriculture or for the production of soil maintenance techniques and will subsequently demonstrate to be insufficient. The idea was to plant sugarcane to monitor their performance in diverse categories of soil.

Soil-cultivating units for the agricultural organization:

The base for using agronomic application from the time when the establishments of manufacture environments in 1994. Brazil’s sugarcane farmers are having a knowledgeable in new distribution and planning scheme. But that is insufficient to confirm the finishing income. Because of other features that may impact the crop, for instance, soil degradation and land preparation. Where sugarcane cultivators organize the land to reduce the level of soil compression, restore the physical characteristic of primary soil, ventilation and water movement reducing soil intensity. Earth arrangement is a costly mechanical process that cannot be used without careful assessment of different soil categories.

1.1 Developments for new categories for sugarcane by technical progression:

This part includes three major breeding plans in Brazil, the principal sugarcane characters chosen over the last periods, the present arrangement of diversities in the sugarcane trade, and upcoming trends for sugarcane production.

1.1.1    Brazilian sugarcane Breeding plan historic characteristic:

The key objective of CTC (sugarcane application center) is to develop in study and growth of new diversities of sugarcane with high production and ability to enhance adapt to agricultural areas.

1.1.2 Key characters of the sugarcane Breeding scheme:

Sugarcane considers as a semi-perennial harvest, from Poaceae homely. The present trade diversities are crossbred from the crossing of sacharumspontaneum,  Saccharum officinarum, and species.

With regards to the studies of Waclawovsky, the saccharum group is a confrontation to upbringing once its cultivars are aneuploidy between species crossbred. Each atom is considered a unique reference to the crossing of the long genome. In order to identify attractive characters such as disease resistance, sugar substance, and cane revenue. It is important to have deep information of the genome and to grow the genetic data related to the multi-chromosome genome for the documentation of exciting genes. The key thematic of the breeding program is to develop high-yielding crop varieties, such as fiber, ethanol, and sugar.

Sugarcane
Process	Main procedure steps	Temperature and pressure	Microorganism	PH	Residence time	Yield	Reference
1	Extraction Additional treatment, Add (yeast) Hydroethanol (5% water) Evaporation Fermentation Use heat resistant device during fermentation	34-37 ° C  (Heat generation in fermentation)	(Invertase dexytran)	–	–	–
2	Washing sugarcane to stir initial cracking process Milling procedure  Add yeast to fermentation Warmed juice Fermentation then distillation (95.5 % ethanol. 5% water) Dilute using molecular strainers.	110 ° C  (Heating juice)	(Saccharomyces cerevisiae)	7	–	95.5% (ethanol)
3	Gathering sugarcane Cleaning using water. Drying Divided sugarcane into small pieces (250 μm – 500 μm). Pretreatment using ion Add cellulose enzyme Hydrolysis Fermentation and add yeast Using membrane	140 ° C  (Pretreatment using ion) 50 ° C (Hydrolysis) 32 ° C (fermentation)	(Saccharomyces cervisiae)	4.8	120 minutes (Pretreatment using ion)  72 hr. (Hydrolysis)	95% (ethanol)
4	(First generation)  Input sugarcane Sugar extraction Sugarcane juice concentration Fermentation Purification	50 ° C  P= 1bar	(Saccharomyces cervisiae)	–	–	Fraction of sugar (0.09)
5	(Second generation)  Pretreatment Pre-hydrolysis Hydrolysis C5 fermentation	50 ° C  P= 1bar	(Saccharomyces cervisiae)	–	40 min (pretreatment)  18hr (Pre-hydrolysis 54 (Hydrolysis ) 9 hr. (C5 fermentation)	The fraction of sugar (0.05)
6	Washing and cutting Drying Grinding Using buffer Add alpha-amylase Sugarcane saccharification Add secondary enzyme Fermentation Distillation	600 ° C (drying)  400 ° C (Sugarcane saccharification 320 ° C (secondary enzyme) 37 ° C (fermentation)	(Saccharomyces cervisiae) (Baker yeast)	4.5	3 days (drying)  48 hrs. (Fermentation)	95%
7	Cleaning feedstock’s Decrease dimension Grinding process Adding (CaOH2)(SO2) Heating Fermentation Supplemental phase	70-80 ° C (grinding)  26-35 ° C (supplemental phase)	Lactic acid	4.5-5.5	7 hrs.	83%
8	Biomass dehydration Crushing Pretreatment Cleaning Dehydration Add yeast Final examine	60 ° C  P= 3 bar (pretreatment)	(scheffersomyces stipites and candida shehatae)	4.8	9.95 min	95%
Beet molasses
9	Cutting peet into fluffy pieces Drying Fermentation	70-80 ° C  (Sugar beet pulp)	(Saccharomyces cervisiae yeast)  (zymomonas mobilis bacteria )	0.2-7.4	–	54.53 g/l (Ethanol)
10	Cutting beet roots into small pieces Extraction Treatment (calcium hydroxide) Heating Distillation	70-80 ° C  (Extraction) 40-75 ° C (Treatment) 85 ° C (Heating)	(Saccharomyces Cerevisiae)	0.2-7.4	–	59.8 g/l (Ethanol)
Sweet sorghum
11	(Gk-coba)  Collecting samples Filtrated Extraction Cleaning Calculate bagasse gross yield Calculate moisture content Dehydration Pretreatment	105 ° C (dehydration)  120 ° C (hydrolysis) 20 ° C (cooling)	Z.mobilis	0.2-5.5 (pretreatment dilute acid)  0.2-6.7 (pretreatment using sulfuric acid)	60 minutes  (Hydrolysis) 30 min (cooling)	394.11 L/fed  (Gk-coba)
12	(Gk-coba)  Collecting samples Filtrated Extraction Cleaning Calculate bagasse gross yield Calculate moisture content Dehydration Pretreatment	105 ° C (dehydration)  120 ° C (hydrolysis) 20 ° C (cooling)	(Sacch.cerevisiae)	0.2-5.5 (pretreatment dilute acid)  0.2-6.7 (pretreatment using sulfuric acid)	60 minutes  (Hydrolysis) 30 min (cooling)	415.87 L/fed  (Gk-coba)
13	(Gk-coba)  Collecting samples Filtrated Extraction Cleaning Calculate bagasse gross yield Calculate moisture content Dehydration Pretreatment	105 ° C (dehydration)  120 ° C (hydrolysis) 20 ° C (cooling)	Mixed culture	0.2-5.5 (pretreatment dilute acid)  0.2-6.7 (pretreatment using sulfuric acid)	60 minutes  (Hydrolysis) 30 min (cooling)	451.69  L/fed (Gk-coba)
14	(Mn-4508)  Collecting samples Filtrated Extraction Cleaning Calculate bagasse gross yield Calculate moisture content Dehydration Pretreatment	105 ° C (dehydration)  120 ° C (hydrolysis) 20 ° C (cooling)	Z.mobilis	0.2-5.5 (pretreatment dilute acid)  0.2-6.7 (pretreatment using sulfuric acid)	60 minutes  (Hydrolysis) 30 min (cooling)	481.09 L/fed (Mn-4508)
16	(Mn-4508)  Collecting samples Filtrated Extraction Cleaning Calculate bagasse gross yield Calculate moisture content Dehydration Pretreatment	105 ° C (dehydration)  120 ° C (hydrolysis) 20 ° C (cooling)	(Sacch.cerevisiae)	0.2-5.5 (pretreatment dilute acid)  0.2-6.7 (pretreatment using sulfuric acid)	60 minutes  (Hydrolysis) 30 min (cooling)	520.38 L/fed (Mn-4508)
17	(Mn-4508)  Collecting samples Filtrated Extraction Cleaning Calculate bagasse gross yield Calculate moisture content Dehydration Pretreatment	105 ° C (dehydration)  120 ° C (hydrolysis) 20 ° C (cooling)	Mixed culture	0.2-5.5 (pretreatment dilute acid)  0.2-6.7 (pretreatment using sulfuric acid)	60 minutes  (Hydrolysis) 30 min (cooling)	553.66 L/fed (Mn-4508)
18	(SS-301)  Collecting samples Filtrated Extraction Cleaning Calculate bagasse gross yield Calculate moisture content Dehydration Pretreatment	105 ° C (dehydration)  120 ° C (hydrolysis) 20 ° C (cooling)	Z.mobilis	0.2-5.5 (pretreatment dilute acid)  0.2-6.7 (pretreatment using sulfuric acid)	60 minutes  (Hydrolysis) 30 min (cooling)	425.18  L/fed (SS-301
19	(SS-301)  Collecting samples Filtrated Extraction Cleaning Calculate bagasse gross yield Calculate moisture content Dehydration Pretreatment	105 ° C (dehydration)  120 ° C (hydrolysis) 20 ° C (cooling)	(Sacch.cerevisiae)	0.2-5.5 (pretreatment dilute acid)  0.2-6.7 (pretreatment using sulfuric acid)	60 minutes  (Hydrolysis) 30 min (cooling)	495.22  L/fed (SS-301
20	(SS-301)  Collecting samples Filtrated Extraction Cleaning Calculate bagasse gross yield Calculate moisture content Dehydration Pretreatment	105 ° C (dehydration)  120 ° C (hydrolysis) 20 ° C (cooling)	Mixed culture	0.2-5.5 (pretreatment dilute acid)  0.2-6.7 (pretreatment using sulfuric acid)	60 minutes  (Hydrolysis) 30 min (cooling)	517.68  L/fed (SS-301

Starch
21	Cut starch into small pieces Separation Heating Add yeast Distillation Molecular filter	85-140 ° C  (Heating)	Lactic acid	5.8-6.2	15-60 min (Heating)	2.85 gallons per bushel (ethanol)
22	Pretreatment Cooking Fermentation Distillation	60 ° C	Enzyme	4.8-5	40 hrs. (Fermentation)	2.7 gals per bushel of (ethanol)  (355-370) Corn yield
23	Cut corn to an independent element Soaking Grinding Liquefaction Saccharification Fermentation Distillation Drying