“\"Using straw to produce alcohol\" breaks through industrialization bottlenecks

What are the production costs? Is cellulose mold produced in-house? According to Tian Guan, the costs are not yet suitable for large-scale production. Could the person who started this discussion please outline the technical strengths and production costs of your company? Thank you!

I don’t believe it! Hehe, during the pilot test phase, too much manual labor was used, and the material transfer process wasn’t taken into account.

This estimate is also based only on model industries; it’s not clear whether subsidies have been obtained, and costs related to collection and transportation, as well as certain other key costs, have not been taken into account. The original poster provided too brief an introduction to this project; it would be better if, in addition to general information, more details about its technical highlights could be offered.

Pay attention to production costs and industrialization. Please, the original poster, provide more detailed information.

Are there any specific figures on production using this patented technology? ? Can you do something about it?

Whether true or not, as a way to utilize alternative energy sources, an attempt was made after all; support is given

The main component of straw is lignocellulose. It is a material made up of a mixture of cellulose, hemicellulose, and lignin. The use of lignocellulose as a sugar source to produce fuel alcohol currently results in very low rates of sugar utilization and conversion, typically only in the teens percent. Lignocellulose, which is formed by the tight binding of cellulose, hemicellulose, and lignin through covalent or non-covalent bonds, accounts for approximately 70-90% of the total weight of straw. The proportion of each of these three components in plants varies depending on the source of the plant or different parts of the plant. The approximate percentages are as follows: cellulose 30-50%, hemicellulose 20-35%, lignin 20-30%, and ash 0-15%. In fact, the amorphous structure of cellulose can be easily broken down; it can be completely degraded into glucose, which serves as a raw material for fermenting ethanol. The main problem at present is that the crystalline structure of cellulose is difficult to break down, preventing further processing from being carried out. Cellulose and hemicellulose are enclosed by recalcitrant lignin, preventing cellulases and hemicellulases from accessing the substrate, which constitutes a major obstacle to the utilization of lignocellulose. Only through effective pretreatment methods that disrupt the advanced structure of lignocellulose and enable cellulase and hemicellulase to access cellulose, can lignocellulose, as the most abundant resource in nature, be fully utilized by humans and animals just like starch. 　　The reaction in which cellulose is hydrolyzed by cellulase is commonly referred to as saccharification, and the main product of this hydrolysis is monosaccharides. In plant cell walls, cellulose is surrounded by hemicellulose and lignin through physical and chemical interactions, which hinders cellulases from attacking cellulose. Lignin is a non-polysaccharide substance formed by the polymerization of phenylpropane. Derivatives of aromatic hydrocarbons are cross-linked with each other through -C-C- and -O- bonds, and their side chains are bonded covalently to hemicellulose, forming a very dense network structure that tightly encloses the cellulose within it. Therefore, to completely degrade cellulose, lignin must be degraded first. The natural structure of untreated plant fiber raw materials contains numerous physical and chemical barriers, resulting in a low hydrolysis yield by cellulase, ranging only from 10% to 20%. The hemicellulose contained in grass plant straws is generally xylan, accounting for 25–30% of the dry weight. Hemicellulose can be degraded into xylose by xylanase (EC3.2.1.8), a hemicellulase. 85-90% of the hydrolysis products of natural hemicellulose is xylose. Producing alcohol through the fermentation of xylose in plant cellulose raw materials can increase the yield of alcohol fermentation from such raw materials by 25% compared to the original level. Therefore, xylose fermentation for alcohol production is a key factor determining the economic viability of producing alcohol from plant fiber resources. The pathway for yeast xylose metabolism is much more complex than that for glucose metabolism. During metabolism, some xylose is converted into other by-products. Therefore, the theoretical yield of alcohol from yeast xylose metabolism is 0.46 grams of alcohol per gram of xylose, which is lower than the theoretical yield of alcohol from glucose fermentation, which is 0.51 grams of alcohol per gram of glucose. The overall reaction equations for the metabolism of glucose and xylose to produce ethanol are as follows: Glucose + ADP + Pi → 2 Ethanol + 2 CO2 + ATP; 3 Xylose + 3 ADP + 3 Pi → 5 Ethanol + 5 CO2 + 3 ATP. Theoretically, 1 ton of glucose can produce 539 kilograms of alcohol (180 units of C6H10O6, under the action of enzymes, yield 88 units of CO2 and 92 units of C2H5OH). Many bacteria, filamentous fungi, and yeasts are capable of producing hemicellulase. Since the extracellular hemicellulase produced by filamentous fungi is easy to isolate and extract, they possess a higher enzyme-producing capacity than ordinary yeasts and bacteria, and can also produce various auxiliary enzymes necessary for breaking down hemicellulose branched structures; these advantages make them suitable for industrial application. Therefore, there has been extensive research on the enzyme production of filamentous fungi, especially those in the genera Trichoderma and Aspergillus. At the same time, the basic properties of the xylanases produced by these two genera, as well as the characteristics of their degradation products, have also been studied in considerable detail. Trichoderma reesei and Aspergillus niger possess stable biological characteristics and the ability to produce high levels of hemicellulase; however, since they also contain cellulase genes, they produce considerable amounts of cellulase when grown in media containing cellulose. Xylose has always been considered unable to be fermented by microorganisms into alcohol. It was not until 1980 that scientists discovered that certain microorganisms could produce alcohol by fermenting xylose. Such as bacteria, filamentous fungi, and yeasts. To date, more than a hundred microorganisms have been found to be capable of metabolizing xylose. Bacteria can ferment a wide range of sugar substances; in addition to monosaccharides, they can also ferment cellulose and biopolysaccharides. However, the drawback of bacterial fermentation is the production of many by-products and a low yield of alcohol. Moreover, bacterial fermentation under high pH conditions is prone to contamination by foreign microorganisms. Like bacteria, fungi can not only ferment monosaccharides but also disaccharides, cellulose, xylan, and the like. This ability of fungi makes them particularly suitable for the simultaneous saccharification and fermentation of plant fiber raw materials. Six species of yeast are capable of producing large amounts of alcohol through the fermentation of xylose (Pachysolen tannophilus, Candida shehatae, Pichia stipitis, Pichia jeiemontii, Zymosporium, and Candida utilis). Compared to bacterial alcohol fermentation, yeast has advantages such as higher alcohol tolerance and fewer by-products. At the same time, lignocellulosic materials fermented by yeast can be used directly as feed without producing toxicity. Yeast alcohol fermentation is not easily contaminated by bacteria and viruses. Saccharomyces cerevisiae is an excellent strain for industrial alcohol production. However, Saccharomyces cerevisiae cannot ferment xylose; it can only ferment its isomer, arabinose. Therefore, efforts are being made to develop engineered bacteria that can co-ferment xylose and glucose to produce alcohol. Swedish scientists genetically engineered Saccharomyces cerevisiae by cloning the entire set of enzyme genes involved in xylose metabolism from fungi that do not produce alcohol, and integrating them into the chromosomes of Saccharomyces cerevisiae, thereby enabling it to convert xylose into alcohol. Research on Zymomonas mobilis is quite noteworthy. Although this bacterium is a prokaryote, it is an anaerobe. But its function is the same as that of Saccharomyces cerevisiae; its enzyme system can efficiently convert hexoses into alcohol. It has a high alcohol yield and conversion rate (1.9 mol of alcohol can be produced from 1 mol of glucose), as well as strong tolerance to alcohol and resistance to inhibitors present in hydrolysates of cellulose-based raw materials. It has advantages such as low cell production and fewer metabolic products, a high fermentation temperature, no need for regular oxygen supply, and a high alcohol production efficiency (it can produce more ethanol than Saccharomyces cerevisiae under the same raw material conditions, by a factor of over 8). But it just can’t ferment xylose. A research team in the United States (Zhang.M) cloned the genes of the pentose metabolism pathway from Escherichia coli into Zymomonas mobilis, enabling it to ferment biomass containing 25%–40% xylose into ethanol. It is precisely because of this difference that using Zymomonas mobilis to produce alcohol can reduce production costs. Engineering microorganisms are microorganisms with special functions created using gene transfer technology; they are also known as genetically modified microorganisms. Using this method to produce alcohol not only achieves a purity of 100% for the alcohol, but also increases production efficiency by 30% compared to the yeast fermentation method. The engineered Klebsiella strain developed by the University of Florida in the United States achieved 80% of the theoretical maximum yield when converting waste paper into alcohol. Fermentation of hemicellulose to produce alcohol: China has mature experience in the hydrolysis of hemicellulose, whether using acid or enzyme methods. The production of xylose and xylitol from hemicellulose hydrolysates is carried out on a certain industrial scale, but there is no production of alcohol via hemicellulose fermentation. Foreign reports indicate that by using special yeast strains, xylose can be fermented into alcohol; it can also be converted into xylulose, which is then fermented into alcohol using ordinary yeast strains. The Renewable Energy Laboratory at Purdue University in the United States used genetic engineering to discover genetically modified enzymes that can convert pentose sugars into ethanol, achieving a major breakthrough in the highly challenging technology of producing ethanol from pentose sugars. This has provided a technical basis for reducing the production costs of fuel ethanol. According to a 1996 report, when the hemicellulose hydrolysate from straw is fermented using Candida, 0.37–0.45 grams of alcohol can be obtained per gram of hydrolysate, resulting in a sugar yield of 37%–45%. The hydrolysis yield of hemicellulose from plant waste is generally 20% to 25%, while it reaches 35% in the case of corn cobs; that is, per ton of plant fiber waste, 10% to 15% alcohol can be obtained from the hemicellulose after hydrolysis. 　　The production of alcohol from plant fiber raw materials involves 4 processes: pretreatment of lignocellulosic raw materials to remove lignin, cellulose, and hemicellulose; saccharification of the sugar solution; fermentation of the sugar solution; and alcohol distillation. Since pentosans account for 10% to 40% of the dry weight of plant fiber raw materials, the hydrolysate of these plant fiber raw materials contains pentoses and hexoses, among which pentoses (mainly xylose) make up about 30%. Therefore, the simultaneous conversion of pentoses and hexoses into alcohol is key to determining the economic viability of producing alcohol from plant fiber raw materials. 　　The main problem currently associated with producing alcohol from renewable plant fiber resources is the high cost. Selecting high-performing cellulase-producing strains and pentose-fermenting strains, as well as further improving the process to reduce production costs, are the directions for future efforts in this field. At present, the technical level for producing alcohol from straw materials both domestically and internationally remains at using cellulase-producing strains (or the cellulase they produce) to break down the straw materials to yield pentoses and hexoses, which are then converted into ethanol by ethanol-fermenting bacteria. Whether it is batch fermentation or mixed fermentation, one must provide the time, raw materials, and equipment required for the growth of both types of bacteria, resulting in production costs that are necessarily higher than those of traditional starch fermentation. Therefore, it is necessary to endow ethanol-fermenting bacteria with the ability to break down straw materials. For many years, people have been trying to recombine a series of genes encoding cellulases and hemicellulases into engineered bacteria capable of producing alcohol through monosaccharide fermentation, so that these bacteria can directly break down straw into monosaccharides, which are then converted into alcohol. In recent years, the U.S. Department of Energy has encouraged the use of sets of enzymes capable of breaking down cellulose and hemicellulose, as well as certain extremophilic bacteria that can ferment pentoses to produce organic acids. Efforts are being made to introduce genes related to ethanol fermentation pathways while eliminating the bacteria’s own organic acid fermentation pathways, in order to create metabolic engineering strains that can use straw for ethanol production; the prospects in this area are very promising. 　　Cellulases are a general term for enzymes that degrade cellulose to produce glucose. It is not an enzyme with a single component, but rather a multi-component complex enzyme system. Cellulases mainly consist of three components: endoglycanase (EC 3.2.1.4, EG), exoglycanase (EC 3.2.1.91, CBH), and cellobiohydrolase (EC 3.2.1.21, CB, also known as β-glucosidase, β-G); each of these components is further composed of several subcomponents. The process of hydrolyzing cellulose to produce glucose relies on the synergistic action of these three components to be completed. Many bacteria, actinomycetes, and fungi can produce cellulase. The strains currently used in the production of cellulase are mainly those from the genera Trichoderma, Aspergillus, Penicillium, and Fusarium, among which Trichoderma reesei from the genus Trichoderma is the most important. In recent years, there has been an increasing number of studies using protoplast fusion technology to improve cellulase-producing strains. The American company Cetus was successful in using genetic engineering techniques to create \"engineered yeast\" that produces cellulase. The company transferred the enzyme-producing genes from Trichoderma reesei into yeast cells; through this \"engineered yeast,\" ethanol and glycerol can be produced directly from cellulose through fermentation. When cellulose is used as a raw material, Saccharomyces cerevisiae finds it difficult to exert its fermentation capabilities. However, cocci, bacilli among microorganisms, as well as some fungi and actinomycetes, can secrete enzymes that break down cellulose—cellulases. Cellulose is first broken down into individual glucose molecules using cellulase, and then Saccharomyces cerevisiae ferments these monosaccharides into ethanol. Microbiologists in countries such as Japan and South Korea have also successfully produced ethanol from cellulose by utilizing the combined action of Trichoderma and Saccharomyces cerevisiae. There is a microorganism called Clostridium thermocellum, which can produce ethanol directly using cellulose as a carbon source. Japan has isolated a thermophilic yeast strain from hot springs; it is capable of producing ethanol using the fibers of straw and waste wood, as well as fermenting pentose sugars such as hemicellulose and xylose into ethanol. In 1996, the National Renewable Energy Laboratory (NREL) in the United States developed a technology for producing alcohol from cellulose waste. The Husco Industrial Group established a 1MW demonstration plant for generating power from rice husks: it processes 12,000 tons of rice husks per year, generates 8 million kWh of electricity annually, and produces 2,500 tons of alcohol per year, achieving significant economic benefits. Canada’s Iogen company uses cellulase produced from genetically engineered fungi to effectively hydrolyze cellulose into glucose and other sugars. At the same time, conventional Saccharomyces cerevisiae is used to ferment glucose into ethanol. Specialized strains can also facilitate the fermentation and conversion of other sugars that are difficult for yeast to ferment, such as pentoses. Iogen Energy owns a demonstration plant worth $22.3 million, a facility for producing ethanol from biomass feedstocks, which is considered to be the largest of its kind in the world. The verification unit can convert 12,000 to 15,000 tons per year of wheat straw into 3 million to 4 million liters per year of fuel-grade ethanol. By using this new technology, production costs can be reduced to about 0.23 cents per liter. This is the world’s first pre-commercial demonstration scale facility for cellulose-based liquor, capable of processing 40 tons of wheat straw per day (using enzymes from the company’s nearby enzyme production plant). The plant controls all the processes involved in cellulose alcohol production, including receiving and preprocessing up to 40 tons of wheat straw material per day, converting cellulose into glucose, as well as carrying out fermentation and distillation. There are 20 employees. Lignin, a by-product of fuel processing. 　　To date, there are dozens of pilot or trial production lines around the world that use plant fiber raw materials to be hydrolyzed into monosaccharides using cellulase, with alcohol being the main end product in most of these cases. These testing or pilot production facilities include the U.S. Army’s Natick Research and Development Center, the University of California’s Lawrence Berkeley Laboratory, the University of Arkansas’ Center for Biomass Research, the University of Pennsylvania, Canada’s Iogen Corporation and Forintek Corporation, the French Petroleum Institute, the Japan Petroleum Alternative Development Association, the Swedish Forest Products Research Laboratory, Lund University in Sweden, the University of Graz in Austria, the Finnish Technology Research Centre, and the Indian Institutes of Technology, among others. According to the Dutch report on the status of bioethanol research and development in May 2003, 211 Mhl (450 PJ) of bioethanol was produced worldwide in 2002: 59% in Brazil, 36% in the United States, 2% in Europe, and 1% each in China, Canada, and Australia. These bio-alcohols all come from traditional raw materials (sugarcane, corn, sugarcane, beet, wheat). The cost price is 0.34 euros per liter (=16.2 euros per GJ), which is twice that of gasoline (7.3 euros per GJ). Raw material costs account for over 50% of the total cost. Furthermore, the limited availability of traditional raw materials poses an obstacle to the widespread use of alcohol as a transportation fuel. The technical process for producing alcohol from lignocellulose currently follows the same approach as that used for beetroot and starch-rich raw materials. The main differences between the two are 1. pretreatment of raw materials, and 2. fermentation of xylose into alcohol. The obstacle to the current technological application of using lignocellulose as a raw material for alcohol production is the generation of large amounts of inorganic waste (gypsum, calcium sulfate) and high costs (0.35 euros/l). The main issue is the high cost of enzymatic hydrolysis, which accounts for 40-55% of the total pure production cost. Another major obstacle is the lack of economically viable xylose fermentation technology. Although significant progress has been made in the study of Z. mobilis and E. coli, a robust microorganism suitable for fermenting pentose sugars has not yet been obtained. Following the improvements to the above process, future costs are expected to drop to 0.23 euros/l (=11 euros/GJ). Commercial production of alcohol from lignocellulosic feedstocks using mature technologies is expected to begin between 2010 and 2015. Although the raw materials and production costs of bio-alcohol are **lower than those of alcohol produced from starch, the lower cost of raw materials is offset by labor costs, supply costs (including water consumption), and depreciation of investments. Therefore, the cost of lignocellulosic alcohol is 75-80% higher than that of alcohol produced from starch. There are two main factors at play here: first, the high cost of pretreatment of lignocellulose; second, the hydrolysis and fermentation processes in the technique involving dilute acid for pretreating lignocellulose take 7 days, whereas alcohol produced from starch requires only 2-3 days. The current price of cellulase is 6,000 euros per ton. It accounts for the largest portion of the cost of cellulose alcohol. The cost of cellulose alcohol is 0.4 dollars per liter, while the cost of starch alcohol is 0.23 dollars per liter. Cellulose alcohol can compete with starch alcohol only when the cost of enzymes is reduced to 1/10 and the investment cost is reduced by 30%.

Are there any devices for producing alcohol from straw in use in China? Could you give some advice, OP? ? Why is there no response just by posting a topic? ?

“CN Energy will build a demonstration plant in Tongshan, Xuzhou this year, with an annual production capacity of 3,000 tons of ethanol. ”It was built last year; has it started operating yet? ?

Sweat! It’s all hype! As far as I know, COFCO Group is at the forefront in terms of production technology for cellulose ethanol. At present, it is still not possible to scale up or industrialize it; it is merely in the experimental stage. There is also Tian Guan, which is involved in speculation; it claims to have reached a certain stage as well. However, **when the relevant authorities went to conduct inspections and verifications, they didn’t even allow them to enter and take a look. All the talk about industrialization is just hype.

12 The OP is right; I completely agree!

It seems that industrial facilities for producing ethanol from real fibers still have a long way to go. I still need to work hard.

The cost is too high, but it should be possible if a good way can be found to eliminate the interference from lignin.

At present, using straw (fibrous materials) to produce alcohol is not yet mature, but it remains a promising direction; breakthroughs have been achieved in some key technologies, and unexpected results have also emerged. The current problem is: 1. The pre-treatment cost of raw materials is high, with large amounts of acids and alkalis required. 2 The large amount of wastewater generated during preprocessing cannot be treated. 3 The final alcohol concentration is low, making extraction difficult. Since the original poster brought up this topic, it seems there is some feasibility to it. For example, the production of packaging box pulp is a highlight, but careful evaluation is still required before putting it into production. “What does it mean that \"for every 5,883 yuan invested, alcohol worth 7,000 yuan can be produced\"? It feels strange. Why are 5,883 yuan and 7,000 yuan used as benchmarks? Wouldn’t it be better to calculate the cost and output per ton of straw or per ton of alcohol?

The project of producing alcohol from straw has not yet been industrialized worldwide due to high costs and severe pollution. These are all factors that limit its development.

Good things are always difficult. At least, everything that leads to something good is not easy.

Whoever breaks through in this direction first will be the best

I agree with what was said on floor 18: this idea is too wonderful to be possible, or the cost of making it a reality would be too high, so it’s better to give up.

It’s just hype; it seems that the costs aren’t even acceptable