FOプロセスの適用によるバイオエタノール生産の向上

Eichhornia crassipes is considered a problem in different aquatic ecosystems, due to its abundance it could become a solution to design and build economic and efficient treatment plants, and especially for the production of biofuels such as bioethanol. The objective of this research is to design and implement a process of sustainable development between phytoremediation and the production of bioethanol with E. crassipes, evaluating the incidence of chromium adhered to the biomass of this plant in the production of bioethanol. A system was installed to evaluate the phytoremediation with E. crassipes with water loaded with chromium, determining the effectiveness of this plant to eliminate this heavy metal even if it is alive in a body of water. After this process, we proceeded to take the biomass loaded with chromium to the bioreactors to evaluate the production of bioethanol, evaluating three types of biomass, one without chromium adhered and the other two with chromium adhered to the structure of its plant. There was a 25% decrease in the ethanol production of E. crassipes due to the presence of chromium. Concluding that the biomass of E. crassipes could be used totally for phytoremediation processes of waters contaminated with heavy metals and later use this biomass for the production of bioethanol, finding a sustainable system to be used on a larger scale.

Bioethanol production by mangrove-derived marine yeast, Sacchromyces cerevisiae

Lignocellulosic biomass generated from different sectors (agriculture, forestry, industrial) act as biorefinery precursor for production of second-generation (2G) bioethanol and other biochemicals. The integration of various conversion techniques on a single platform under biorefinery approach for production of biofuel and industrially important chemicals from LCB is gaining interest worldwide. The waste generated on utilization of bio-resources is almost negligible or zero in a biorefinery along with reduced greenhouse gas emissions, which supports the circular bioeconomy concept. The economic viability of a lignocellulosic biorefinery depends upon the efficient utilization of three major components of LCB—cellulose, hemicellulose and lignin. The heterogeneous structure and recalcitrant nature of LCB is main obstacle in its valorization into bioethanol and other value-added products. The success of bioconversion process depends upon methods used during pre-treatment, hydrolysis and fermentation processes. The cost involved in each step of the bioconversion process affects the viability of cellulosic ethanol. The lignocellulose biorefinery has ample scope, but much-focused research is required to fully utilize major parts of lignocellulosic biomass with zero wastage. The present review entails lignocellulosic biomass valorization for ethanol production, along with different steps involved in its production. Various value-added products produced from LCB components were also discussed. Recent technological advances and significant challenges in bioethanol production are also highlighted in addition to future perspectives.Graphical abstract

Abstract. Purwoko Tj, Sari SLA, Mahadjoeno E, Sunarto. 2017. Bioethanol production from rice and corn husks after enzymatic and microbes hydrolysis and yeast fermentation. Bioteknologi 14: 19-23. Bioethanol is a renewable resource that can be produced from fermented cellulosic biomass. The use of lignocellulosic materials from agricultural wastes provides a low-cost fermentative substrate. Lignocellulosic ethanol production involves acid or enzymatic hydrolysis. The enzymatic hydrolysis cost higher, however in environmental issue this step is favorable. The purpose of this research was to compare bioethanol production after microbes and cellulosic enzymes hydrolysis following yeast, Saccharomyces cerevisiae, fermentation from rice and corn husks. The rice and corn husks (1 kg) were each suspended in water until the volumes reached 5 L. The sample mixtures were treated with 2.5 mg/L cellulases, 5 g/L multienzymes, and 5 mL/L EM4 respectively. The mixtures were stirred for 24 hours at pH 5.7 and 35°C. After hydrolysis, the samples (100 mL) were treated by 1, 2, and 3 % w/v Baker’s yeasts. The samples were fermented with incubator shaking for 6 days at 30°C, 90 rpm, and pH 6.5. Sugar concentrations were determined by dinitrosalicylic acid (DNS) colorimetric method. Bioethanol production and specific gravity method were then compared to IAOC Ethanol Table. Sugar concentrations and bioethanol production after multienzymes hydrolysis of rice and corn husks. There were 6.54-6.81 mg/mL and 3.17-3.54 mg/mL, respectively. Sugar concentrations of rice and corn husks after multienzymes hydrolysis treatment was higher than EM4 and cellulases hydrolysis treatments. Therefore, bioethanol productions of rice and corn husks after multienzymes hydrolysis and yeasts after 2 days fermentation were higher than the others.

Effects of harvest time on bioethanol production and bagasse characteristics for combustion and forage in sweet sorghum

PurposeThis study aims to assess the effect of water variation on bioethanol production from cassava peels (CP) using Saccharomyces cerevisiae yeast as the ethanologenic agent.Design/methodology/approachThe milled CP was divided into three treatment groups in a small-scale flask experiment where each 20 g CP was subjected to two-stage hydrolysis. Different amount of water was added to the fermentation process of CP. The fermented samples were collected every 24 h for various analyses.FindingsThe results of the fermentation revealed that the highest ethanol productivity and fermentation efficiency was obtained at 17.38 ± 0.30% and 0.139 ± 0.003 gL−1 h−1. The study affirmed that ethanol production was increased for the addition of water up to 35% for the CP hydrolysate process.Practical implicationsThe finding of this study demonstrates that S. cerevisiae is the key player in industrial ethanol production among a variety of yeasts that produce ethanol through sugar fermentation. In order to design truly sustainable processes, it should be expanded to include a thorough analysis and the gradual scaling-up of this process to an industrial level.Originality/valueThis paper is an original research work dealing with bioethanol production from CP using S. cerevisiae microbe.HighlightsHydrolysis of cassava peels using 13.1 M H2SO4 at 100 oC for 110 min gave high Glucose productivityHighest ethanol production was obtained at 72 h of fermentation using Saccharomyces cerevisiaeOptimal bioethanol concentration and yield were obtained at a hydration level of 35% agitationHighest ethanol productivity and fermentation efficiency were 17.3%, 0.139 g.L−1.h−1

Bioethanol production from renewable sources to be used in transportation is now an increasing demand worldwide due to continuous depletion of fossil fuels, economic and political crises, and growing concern on environmental safety. Mainly, three types of raw materials, that is, sugar juice, starchy crops, and lignocellulosic materials, are being used for this purpose. This paper will investigate ethanol production from free sugar containing juices obtained from some energy crops such as sugarcane, sugar beet, and sweet sorghum that are the most attractive choice because of their cost-effectiveness and feasibility to use. Three types of fermentation process (batch, fed-batch, and continuous) are employed in ethanol production from these sugar juices. The most common microorganism used in fermentation from its history is the yeast, especially, Saccharomyces cerevisiae, though the bacterial species Zymomonas mobilis is also potentially used nowadays for this purpose. A number of factors related to the fermentation greatly influences the process and their optimization is the key point for efficient ethanol production from these feedstocks.

Alternative substrates to produce useful chemicals such as biofuel have been attractive, in particular, for cellulosic ethanol production. In this context, the objective of this work was optimized the synergistic mixture of enzymes and bioethanol production. The enzymes of Trichoderma reesei and crude enzyme extract from Lichtheimia ramosa were used in the hydrolysis of mature coconut fibre pretreated by sequential process of alkaline hydrogen peroxide (Alk-H2O2)-sodium hydroxide (NaOH). Furthermore, these enzymes and pretreated vegetable biomass were applied in the bioethanol production by Saccharomyces cerevisiae in semi-simultaneous saccharification and fermentation strategy (SSSF). Resulting in the yields and conversions of delignified mature coconut fibre into reducing sugars between 12.7-82.14% and 0.09-0.64 g reducing sugars/g dry biomass, respectively, with an initial hydrolysis rate at 12 h between 0.10-0.89 g/(L.h). Yields and conversions of delignified mature coconut fibre into glucose between 10.16-83.78% and 0.06-0.43 g glucose/g dry biomass, in that order, with an initial hydrolysis rate at 12 h between 0.03-0.35 g/(L.h). Bioethanol production by S. cerevisiae using delignified mature coconut fibre, enzymes from T. reesei and crude enzyme extract from L. ramosa resulted in the production of 4.62 g/L, yield of 0.41 g ethanol/g glucose and volumetric productivity of ethanol of 0.13 g/(L.h), respectively. The results showed synergistic effects between enzymes from T. reesei and crude enzyme extract from L. ramosa, without promoting inhibition in the alcoholic fermentation. Therefore, allowing to formulate an optimized enzymatic preparation aiming cellulosic ethanol production.

Depleting fossil fuels target plant weeds which have the potential to be converted into efficient biofuels. In this study, mimosa seeds were utilized as a substrate for bioethanol production. This investigation was divided into three parts: breaking dormancy of seeds, mimosa seeds germination, and bioethanol production from mimosa seeds. Seed dormancy breaking was initiated by seeds soaked in hot distilled water to analyze the sugar quantity. Sugar content was measured relevance with root length results. According to results, root length obtained revealed that at 0.5-1.0 cm for root size has the most sugar availability. It was revealed that the total sugar 548.21 g/L and reducing sugar has a concentration of 248.67 g/L. Therefore, the broken dormancy of seeds using hot water at 95°C for 10min with a root length of 0.5-1cm was used for ethanol fermentation. Ethanol fermentation was done by free yeast cell and immobilized yeast by injecting yeast directly. The ethanol yield was measured on the 3rd day of every fermentation. Results showed that the free cell yeast during the 1st day of fermentation afforded an ethanol production of 57.574g/L, while the yield for immobilized yeast was 60.714g/L. Consequently, the ethanol yield on the 2nd day of fermentation from the directly injected immobilized yeast was 60.088g/L. Results revealed that the immobilization of yeast cells in fermentation provided a higher probability for bioethanol yield and could be utilized as a baseline for future bioethanol production. Stimulation of natural enzymes by germination of seeds for enhanced bioethanol production will be a novel approach towards next-generation biofuels.

Biochemical features and bioethanol production of microalgae from coastal waters of Pearl River Delta

Perspectives in the production of bioethanol: A review of sustainable methods, technologies, and bioprocesses

By-products from various industries can be used in animal feeds.One example concerns the use of distillers' grains and spent yeast from brewing and distilling processes (including bio-ethanol production).As the fermentation reaction for bio-ethanol production is susceptible to contamination by microorganisms, in particular lactic acid bacteria, antibiotics can be used to control such unwanted bacteria.Therefore, by-products from bio-ethanol production used in animal feed can potentially contain residues of the antibiotics applied.This is undesirable as, in the EU, the presence of antibiotics in feed other than for therapeutic reasons is de facto prohibited.The aim of this project was to gain insight into the potential presence of antibiotic residues in fermentation by-products intended for animal feed, by means of literature analysis and expert interviews.This study, therefore, presents an overview of by-products from fermentation processes for use in animal feed in the Netherlands as well as import data of such by-products.Furthermore, an overview with examples of fermentation aids containing antimicrobial substances is included, as well as an overview of studies on the detection of antibiotic residues in by-product samples from bio-ethanol fermentation.Key findings from this study are:1.The main imported by-products from fermentation processes originate from brewing or distilling processes, which include bio-ethanol production, such as brewers' grains, distillers' grains or vinasse.2. Antibiotics are used in bio-ethanol fermentation outside the EU to control unwanted contaminants, and such products are widely available.3. Several recent studies report on the detection of antibiotic residues in brewers' and distillers' grains samples (e.g., erythromycin, penicillin, and virginiamycin residues), which may be a hazard when such feed products are imported.4. By-products from fermentation processes from the bio-based industry, for example the production of additives, enzymes, and flavourings, are often not used in animal feed.These side-streams, therefore, do not contribute to an increased risk of antibiotics in animal production. 5.For the monitoring of potential presence of antibiotic residues in feed, we recommend screening of byproducts from ethanol production, in particular from regions outside the EU where fermentation aids containing antibiotics are widely available.

The performance of the alkaline fungal laccase PIE5 (pH 8.5) in the delignification and detoxification of alkali-pretreated corncob to produce bioethanol was evaluated and compared with that of the neutral counterpart (rLcc9, 6.5), with the acidic laccase rLacA (4.0) was used as an independent control. Treatment with the three laccases facilitated bioethanol production compared with their respective controls. The lignin contents of alkali-pretreated corncob reduced from 4.06%, 5.06%, and 7.80% to 3.44%, 3.95%, and 5.03%, after PIE5, rLcc9, and rLacA treatment, respectively. However, the performances of the laccases were in the order rLacA > rLcc9 > PIE5 in terms of decreasing total phenol concentration (0.18, 0.36, and 0.67 g/l), boosting ethanol concentration (8.02, 7.51, and 7.31 g/l), and volumetric ethanol productivity (1.34, 0.94, and 0.91 g/l hr), and shortening overall fermentation time. Our results would inform future attempts to improve laccases for ethanol production. Furthermore, based on our data and the fact that additional procedures, such as pH adjustment, are needed during neutral/alkaline fungal laccase treatment, we suggest acidic fungal laccases may be a better choice than neutral/alkaline fungal laccases in bioethanol production.

ABSTRACTBACKGROUNDThe effect of process integration in bioethanol productivity was experimentally evaluated by coupling an ethanol‐selective pervaporation module to a simultaneous saccharification–fermentation process (SSF). Ethanol concentration in the permeate stream and ethanol productivity were evaluated. Polydimethylsiloxane (PDMS) and silicalite, pure and composite multilayer membranes, supported on porous stainless steel disks, were synthesized and used. Selectivity tests were conducted using ethanol–water mixtures and fermentation broths (5–12 wt% ethanol).RESULTSMultilayer composite membranes showed the best performance among the membranes studied; separation factor, permeance and ethanol concentration in the permeate stream were 31.4, 5.39 kg m−2 h−1 bar−1 (959 gas permeation units (gpu)) and 81.77 wt%, and 26.5, 5.02 kg m−2 h−1 bar−1 (894 gpu) and 77.41 wt%, with model solutions (12.76 wt% ethanol) and actual fermentation broths (11.69 wt% ethanol), respectively. The coupled pervaporator–SSF system, using silicalite‐PDMS multilayer composite membranes, achieved ethanol concentrations in the permeate up to 71.53 wt% and an increase of 3% in productivity with respect to the SSF process without in situ removal of ethanol; permeance and separation factor in the coupled system were 3.25 kg m−2 h−1 bar−1 (578.4 gpu) and 24.8, respectively.CONCLUSIONSThe integrated process improves bioreactor productivity and could reduce the energy penalty in the distillation process conventionally used in bioethanol production. © 2016 Society of Chemical Industry

Efficient bioethanol production from date palm (Phoenix dactylifera L.) sap by a newly isolated Saccharomyces cerevisiae X19G2