Potential For Bioethanol Production Research Articles

Mathematical modelling of quantifying bioethanol fuel production from pineapple waste

Lack of confidence in potential bioenergy production and net benefit hinders rapid implementations of such sustainable energy productions from different waste sources. With the aim of accelerating real-life implementations of more bioenergy productions, this paper presents development of a simple mathematical model, which can be used to evaluate potential bioethanol production capacity from pineapple waste under different input conditions. Based on an earlier experimental study, the mathematical model was developed depending on three contributing factors; pH, temperature and substrate concentration as considered in the earlier experimental study. Results from the developed mathematical formulation were compared with the experimental data from the earlier original study. It is found that the developed model is quite capable to estimate potential bioethanol productions from pineapple waste. Model estimated results are having a coefficient of correlation of 0.84 with the measured data. Standard errors of the model’s estimations are also quite low; RMSE = 0.49, MAE = 0.39 and RAE = 0.06. To facilitate a wider industrial generation, a basic mathematical model framework for economic analysis is proposed involving evaluation of net present values of expected future yields, as well as costs (initial and maintenance). Such mathematical model of economic analysis will help stakeholders on selecting optimum input parameters in achieving targeted benefit through optimised energy consumption.

A Study on the Potentiality of Bioethanol Production from Selected Weed Species of the Asteraceae Family


 
 
 Increasing population growth, industrialization, and the harmful impacts of fossil fuel burning on the environment fascinated the researchers to find a low-cost, environmentally friendly alternative substitute. A potential substitute feedstock for the synthesis of second-generation bioethanol is the lignocellulosic biomass from invasive weedy plants. The aim of this study was to determine the potential of bioethanol production from two weedy plant species using physical, chemical, and physiochemical pretreatment methods, as well as to optimize the pretreatment and culture conditions to obtain a higher reducing sugar amount and ethanol yield. The collected invasive weedy plants, Chromolaena odorata and Tridax procumbens, were cleaned, then pretreated with different acids and bases (4% v/v) at 121oC for 15 min. Then the filtrate was incubated with Saccharomyces cerevisiae (baker‘s yeast) in the peptone yeast extract and nutrient medium (PYN) at room temperature, the pH was maintained at 5.0. T. procumbens plant substrate with the performic acid pretreatment agent produced a significant amount (0.2%) of ethanol, and further studies were conducted with the same substrate and the pretreatment agent. The conditions were optimized successively by changing one factor at a time while keeping the other variables constant. Several important hydrolysis factors were studied for the optimization, including performic acid concentration (0.2–5%), hydrolysis time (10–60 min), fermentation time (24–120 h), inoculum concentration (1.25–7.5 g/100 ml), and rotation speed (50–250 rpm). The maximum ethanol yield of 0.47% was observed at 0.6% performic acid concentration, 30 min of hydrolysis time, 48 h of fermentation time, 5 g/100 ml of inoculum concentration, and 100 rpm rotation speed with T. procumbens using S. cerevisiae.
 Keywords: Bioethanol, Lignocellulosic biomass, Acid hydrolysis, Saccharomyces cerevisiae
 
 

Screening and characterization of potential bioethanol production yeast from tropical fruits

This study aims to separate and characterise indigenous yeast (IY) from tropical fruit waste. The techniques include isolating and characterising yeast from different kinds of fruit waste, testing yeast for ethanol and glucose tolerance, and producing bioethanol in vitro. Using a microscope and visual inspection, the yeast’s morphological identification is done. Using a spectrophotometer to measure optical density, the tolerance tests for glucose and ethanol are used to select yeast biochemically. With the Gas Chromatography-Flame Ionisation Detector (GC-FID), one can measure the amount of ethanol present. Yeast was isolated using selective media to yield six isolates: code A1 from grapes, codes NG1, NG2 from jackfruit, and codes N1, N2, and N3 from pineapple; mango produced no results. Three isolates with the codes A1, NG1, and NG2 were chosen based on test results for resistance to glucose and ethanol. The Saccharomyces cerevisae bioethanol production test yielded 6.60%, 3.30%, 4.5%, and.4.85% of ethanol for the yeast species coded A1, NG1, and NG2, respectively, in terms of ethanol. According to the study’s findings, yeast bearing the NG2 code may be used in the fermentation process to produce bioethanol.

Enhancing Bioethanol Production from Rice Straw through Environmentally Friendly Delignification Using Versatile Peroxidase.

Rice straw (RS), an agricultural residue rich in carbohydrates, has substantial potential for bioethanol production. However, the presence of lignin impedes access to these carbohydrates, hindering efficient carbohydrate-to-bioethanol conversion. Here, we expressed versatile peroxidase (VP), a lignin-degrading enzyme, in Pichia pastoris and used it to delignify RS at 30 °C using a membrane bioreactor that continuously discarded the degraded lignin. Klason lignin analysis revealed that VP-treatment led to 35% delignification of RS. We then investigated the delignified RS by SEC, FTIR, and SEM. The results revealed the changes of RS caused by VP-mediated delignification. Additionally, we compared the saccharification and fermentation yields between RSs treated with and without VP, VP-RS, and Ctrl-RS, respectively. This examination unveiled an improvement in glucose and bioethanol production, VP-RS exhibiting up to 1.5-fold and 1.4-fold production, respectively. These findings underscore the potential of VP for delignifying RS and enhancing bioethanol production through an eco-friendly approach.

Comparative Assessment of Ethanol Production from Six Typical German Waste Baked Products

AbstractThis study investigates the potential for bioethanol production of six types of typical German leftover baked products: bread rolls, pretzel rolls, fine rye bread, white bread, pastry, and cream cakes. The experimental setup consisted of two experiments—one as a control and another with the addition of diammonium phosphate (DAP) to the mash. In terms of monosaccharide concentration at 30% dry matter (DM), white bread mash exhibited the highest level at 251.5 g/L, while cream cakes mash had the lowest at 186 g/L. The highest ethanol production occurred after 96 h of fermentation with rye bread, yielding 78.4 g/L. In contrast, despite having the highest monosaccharide levels, white bread produced only 21.5 g/L of ethanol after 96 h. The addition of DAP accelerated monosaccharide consumption in all baked products, with cream cakes completing the process in just 24 h. Bread rolls, pretzel rolls, pastry, and white bread fermentations finished within 72 h. Ethanol yields significantly increased in three DAP samples, with pretzel rolls yielding the highest ethanol concentration at 98.5 g/L, followed by white bread with 90.6 g/L, and bread rolls with 87.7 g/L. DAP had a substantial impact on all samples, reducing fermentation time and/or increasing ethanol yield. This effect was particularly pronounced with white bread, where it improved conversion efficiency from 17 to 72%, resulting in 90.6 g/L of ethanol. These results demonstrate that waste baked products hold substantial potential for bioethanol production, and this potential can be further enhanced through the addition of DAP. Graphical Abstract

Evaluation of Bioethanol Yield Potential of Different Sweet Sorghum Cultivars Grown as a Second Crop Under Eastern Mediterranean Conditions

Sweet sorghum has a high potential for bioethanol production due to its high fermentable sugar content and biomass yield. This research was carried out to evaluate bioethanol yield potential of six sweet sorghum cultivars (ICSV 93046, ICSV 700, Black Amber, White African, Gülşeker, and Red’s Red) during summer growing season of 2022 under eastern Mediterranean conditions. Cultivars were significantly differed for brix degree, green herbage yield, juice yield, and juice ethanol yields in the study. ICSV 93046 produced the significantly highest fresh stem yield (58811 kg/ha), juice yield (16105 kg/ha), and juice ethanol yield (1194 L/ha) and followed by ICSV 700. On the other hand, the significantly lowest brix degree (10.5 ◦ Bx) and juice ethanol yield (322 L/ha) were achieved by Gülşeker. These results suggested that ICSV 93046 was the most suitable cultivar to be grown as a second crop for bioethanol production under eastern Mediterranean conditions.

ASSESSMENT OF AGROBIOMAS POTENTIAL OF AGRICULTURE OF UKRAINE FOR THE PRODUCTION OF BIOFUELS

The need to develop the potential of agrobiomass for the production of biofuels is justified, which will make it possible to partially ensure the energy security of the state in the conditions of martial law. The volumes of cultivation of the main agricultural crops and the number of livestock in the field of livestock breeding in Ukraine were determined. The structure of the use of fuel and energy resources in the agro-industrial sector of the country was analyzed and the possibility of replacing oil products in the general energy balance with biodiesel and bioethanol was established. It was determined that the volume of rapeseed production in 2022 has increased by 12.9% compared to the previous year, and the increase in the price of gas oil and disruption of the logistics chains of the export of agricultural products determines the economic feasibility of processing this crop. It has been proven that the use of advanced biogas production technologies will make it possible to increase the level of environmental security of the state, optimize the content of humus in the soil due to the use of digestate, and increase the level of energy security of the state. It was determined that the total consumption of fuel and energy resources by agro-industrial complex formations in Ukraine amounted to 3.84 million tons of equivalent fuel or 2.69 million toe, and the total consumption of these resources was 86.4 million toe. It was established that the consumption of energy resources by agro-industrial complex enterprises was only 3.1% of the total consumption. It was determined that using the potential of agro-biomass of the agricultural industry will make it possible to annually obtain: 3.444 billion m3 of biogas, 1.2 million tons of biodiesel, 10.4 million tons of bioethanol, and 1.59 billion tons of solid biofuels from post-harvest residues. It has been established that the use of the energy potential of the agricultural sector will make it possible to almost completely meet the needs of not only this sector of the economy, but also the entire country in gas oil due to the production of biofuel, and the potential of bioethanol production can be partially used for export. The need to develop biofuel production at both agro-industrial complex enterprises and households has been identified. It has been proven that the use of the advanced technologies for transporting liquid digestate and injecting it will reduce the costs of agricultural formations and increase the content of humus in the soil.

Ethanologenesis from glycerol by the gut acetogen Blautia schinkii.

The human gut is an anoxic environment that harbours a multitude of microorganisms that not only contribute to food digestion. The microbiome is also involved in malfunctions such as diseases, inflammation processes or development of obesity, but it is also involved in processes that increase the human well-being. Both, the good and the bad, are mediated by fermentation end products of bacterial metabolism, among others. However, despite a steadily growing knowledge of 'who lives out there', little in known of 'what do they do out there'. The genus Blautia is commonly found in the gut and associated with human well-being, but the exploration of their metabolic potential has just started. We demonstrate that B. schinkii grows on glycerol by producing acetate and ethanol. Transcriptome studies and biochemical analyses revealed a glycerol dehydrogenase and dihydroxyacetone kinase that funnel the substrate into glycolysis. Consequently, cells also grew on dihydroxyacetone. Cells could be adapted to grow at high (up to 1.5 M) glycerol concentrations but then only ethanol was formed. Ethanol production from glycerol is not only of relevance for the human host but also for potential bioindustrial production of bioethanol from waste glycerol.

Integrated application of morphological, anatomical, biochemical and physico-chemical methods to identify superior, lignocellulosic grass feedstocks for bioenergy purposes

Grasses have sufficient potential to be used in the biofuel industry due to many reasons. Hence, systematic assessments of the lignocellulosic biomass obtained from six grasses namely Arundo donax, Chrysopogon zizanioides, Coix lacryma-jobi, Pennisetum purpureum, Saccharum spontaneum, and Sorghum bicolor have been performed to assess their potential for bioethanol production. Selected morphological (height, internode diameter, number of internodes, fresh biomass, dry biomass, total volatile matter), anatomical (vascular bundle, stain intensity), analytical (crystallinity index of cellulose, thermal stability, hemicellulose, moisture content) and biochemical (α-cellulose, acid insoluble lignin) parameters were investigated and statistically analysed to detect the superior grass species. The study indicates that S. spontaneum harbours promising biofuel potential by having high dry biomass (56.33 g), α-cellulose (55.88–67.76%), but lower thermal stability (Tmax: 344.37 °C). Comparable ligno-cellulose properties with respect to dry biomass (54.60 g), α-cellulose content (45.95–64.14%), Tmax (360.51 °C) have been observed for A. donax. However, relatively higher lignin contents (∼17–23%) and crystalline cellulose (43.63%–46.96%) in S. spontaneum and A. donax might have resulted into lesser saccharification yield (216.04–230.08 mg/g). On that aspect, S. bicolor and C. lacryma-jobi might be useful since they possessed lower lignin (14.03–16.56%) and crystalline cellulose (32.51–33.02%) leading to higher glucose yield (263–420.06 mg/g). Taken together, this study indicates that integration of morphological, biochemical, and analytical properties of biomasses are complex, yet useful to predict a ‘superior donor plant’ for bioenergy purposes.

Evaluation of Saccharomyces cerevisiae Improved Strains Potential in the Bioethanol Production from Bagasse

Plant biomass can be utilized to produce bioethanol, because they are abundantly available in nature. The cost of ethanol production from lignocellulosic materials is relatively high with low yield. But this can be solved by strain improvement processes. This study is aimed at evaluate bioethanol production potential of improved strains of Saccharomyces cerevisiae developed through random mutagenesis. Bagasse was hydrolysed with 1% NaOH and 1.0M H2SO4 respectively for five days. The hydrolysed bagasse was saccharified using Aspergillus niger isolated from soil samples. Saccharomyces cerevisiae isolated from locally produced wines; sorghum (burukutu) oil palm wine (emu) and raphia palm wine (oguro) with the highest ethanol production (5.0g/ml) were used, and then treated with physical mutagen (ultraviolet light) and chemical mutagens (Acridine dye, Bromo acetaldehyde, dithiothreitol, Ketoconazole and Nitrous acid) respectively to develop mutant with high ethanol producing efficiency under varied operational parameters. Three mutant strains of Saccharomyces cerevisiae namely;- SUV, SCD and SCK produced higher volumes of ethanol (7.5 g/ml, 9.8 g/ml, 11.2 g/ml respectively). SCD and SCK were able to grow at 25% ethanol concentration indicating that they had higher ethanol tolerance ability than the other strains. The optimum temperature and pH for ethanol production by all the strains were 350C and 6.0 respectively. The improved strains of Saccharomyces cerevisiae developed through random mutation techniques had produced more ethanol from the bagasse than the wild-type.

Prospects of Bioethanol from Agricultural Residues in Bangladesh

Bangladesh is a middle-income country. With the development of the industrial and agricultural sectors, the demand for petroleum-based fuels in the transport sector has been steadily growing. Diesel, petrol, octane (C8H18), liquid petroleum gas (LPG), and compressed natural gas are mainly used as fuels in the transportation sectors of Bangladesh. The government imports LPG as well as refined, crude, and furnace oil from abroad to meet the country’s growing energy demand. Apart from that, Bangladesh has a shortage of natural gas reserves, which is a great concern. As a result, it is essential to find and use renewable fuel sources. Since Bangladesh is an agricultural country, bioethanol could be the best alternative fuel generated from agricultural residues and waste. Every year, a large amount of agricultural residue is generated in this country, from which a vast amount of bioethanol could be produced. Bioethanol derived from agricultural residue and waste can reduce dependency on fossil resources, reduce fossil fuel’s environmental impact, and improve engine performance. This article comprehensively reviews the bioethanol production potential from agricultural residues and investigates the opportunities and possibilities in Bangladesh. The research outcomes reveal that in the fiscal year 2019–2020, approximately 46.5 million tons of agricultural residue were generated from the available major crops, from which about 19.325 GL (gigalitres) of bioethanol could be generated. This current study also investigates the practical methods of bioethanol production from different agricultural feedstocks and identifies the challenges related to bioethanol production in Bangladesh.

Bioethanol production from sorghum grain with Zymomonas mobilis: increasing the yield and quality of raw distillates.

The present study aimed to demonstrate the superiority of bioethanol yield and its quality from sorghum using the granular starch degrading enzyme Stargen™ 002 over simultaneous saccharification and fermentation, and separate hydrolysis and fermentation using Zymomonas mobilis CCM 3881 and Ethanol Red® yeast. Bacteria were found to produce ethanol at higher yield than the yeast in all fermentations. The highest ethanol yield was obtained with Z. mobilis during 48 h of simultaneous saccharification and fermentation (83.85% theoretical yield) and fermentation with Stargen™ 002 (81.27% theoretical yield). Pre-liquefaction in fermentation with Stargen™ 002 did not improve ethanol yields for both Z. mobilis and Saccharomyces cerevisiae. Chromatographic analysis showed twice less total volatile compounds in distillates obtained after bacterial (3.29-5.54 g L-1 ) than after yeast (7.84-9.75 g L-1 ) fermentations. Distillates obtained after bacterial fermentation were characterized by high level of aldehydes (up to 65% of total volatiles) and distillates obtained after yeast fermentation of higher alcohols (up to 95% of total volatiles). The process of fermentation using granular starch hydrolyzing enzyme cocktail Stargen™ 002 resulted in low amounts of all volatile compounds in distillates obtained after bacterial fermentation, but the highest amounts in distillates obtained after yeast fermentation. The present study emphasizes the great potential of bioethanol production from sorghum with Z. mobilis using granular starch hydrolyzing enzyme Stargen™ 002, which leads to reduced water and energy consumption, especially when energy sources are strongly related to global climate change. © 2023 Society of Chemical Industry.

Potential of Pine Needle Biomass for Bioethanol Production

Currently, fossil fuels are used to produce fuels and electricity, which are finite sources and have a negative impact on the natural environment. An excellent alternative to these fuels is biofuels, such as bioethanol from waste forest biomass. Pine needles are one of the most important available forest biomass materials with s significant impact on local understory vegetation. Forest waste biomass, which is a rich source of lignocellulose, can be used in various ways, such as for the eco-economical production of bioethanol. The aim of this study was to analyze the possibilities of bioethanol production from pine needle biomass obtained from forest land following different soil preparations and logging residue management. The pine needle dry matter yield, chemical components of pine needle biomass (cellulose, hemicellulose, lignin), and the amount of ethanol yield per hectare were evaluated. The highest average yield pine needle equal to 6.17 Mg∙ha−1 was observed. Bioethanol yield per hectare from this biomass was the highest for plowing with the LPZ-75 plow and was 1.08 m3∙ha−1. The discussed results were confirmed by detailed statistical analysis. To sum up, the researched pine needle biomass turned out to be an interesting raw material with the potential for bioethanol production.

Comparative study of ethanol production from sodium hydroxide pretreated rice straw residue using Saccharomyces cerevisiae and Zymomonas mobilis.

Rice straw is a suitable alternative to a cheaper carbohydrate source for the production of ethanol. For pretreatment efficiency, different sodium hydroxide concentrations (0.5-2.5% w/v) were tested. When compared to other concentrations, rice straw processed with 2% NaOH (w/v) yielded more sugar (8.17 ± 0.01mg/ml). An alkali treatment induces effective delignification and swelling of biomass. The pretreatment of rice straw with 2% sodium hydroxide (w/v) is able to achieve 55.34% delignification with 53.30% cellulose enrichment. The current study shows the effectiveness of crude cellulolytic preparation from Aspergillus niger resulting in 80.51 ± 0.4% cellulose hydrolysis. Rice straw hydrolysate was fermented using ethanologenic Saccharomyces cerevisiae (yeast) and Zymomonas mobilis (bacteria). Overall, superior efficiency of sugar conversion to ethanol 70.34 ± 0.3% was obtained with the yeast compared to bacterial strain 39.18 ± 0.5%. The current study showed that pretreatment with sodium hydroxide is an effective method for producing ethanol from rice straw and yeast strain S. cerevisiae having greater fermentative potential for bioethanol production than bacterial strain Z. mobilis.

Fabrication and Characterization of Carbon Nanotube Filled PDMS Hybrid Membranes for Enhanced Ethanol Recovery.

Ethanol separation via the pervaporation process has shown growing application potential in solvent recovery and the bioethanol industry. In the continuous pervaporation process, polymeric membranes such as hydrophobic polydimethylsiloxane (PDMS) have been developed to enrich/separate ethanol from dilute aqueous solutions. However, its practical application remains largely limited due to the relatively low separation efficiency, especially in selectivity. In view of this, hydrophobic carbon nanotube (CNT) filled PDMS mixed matrix membranes (MMMs) aimed at high-efficiency ethanol recovery were fabricated in this work. The filler K-MWCNTs was prepared by functionalizing MWCNT-NH2 with epoxy-containing silane coupling agent (KH560) to improve the affinity between fillers and PDMS matrix. With K-MWCNT loading increased from 1 wt % to 10 wt %, membranes showed higher surface roughness and water contact angle was improved from 115° to 130°. The swelling degree of K-MWCNT/PDMS MMMs (2 wt %) in water were also reduced from 10 wt % to 2.5 wt %. Pervaporation performance for K-MWCNT/PDMS MMMs under varied feed concentrations and temperatures were evaluated. The results supported that the K-MWCNT/PDMS MMMs at 2 wt % K-MWCNT loading showed the optimum separation performance (compared with pure PDMS membranes), with the separation factor improved from 9.1 to 10.4, and the permeate flux increased by 50% (40-60 °C, at 6 wt % feed ethanol concentration). This work provides a promising method for preparing a PDMS composite with both high permeate flux and selectivity, which showed great potential for bioethanol production and alcohol separation in industry.

Bioethanol: A New Synergy between Marine Chitinases from Bacillus haynesii and Ethanol Production by Mucor circinelloides

The fourth generation of bioethanol production is on a lookout for non-lignocellulosic biomass waste. One such candidate is chitin, the second most abundant biopolymer on earth. However, the crystalline nature of chitin hinders its application potential for bioethanol production. This limitation can be circumvented by hydrolysing this polymer into oligomers using chitinases. We used this hypothesis and isolated a Bacillus haynesii, a marine bacterium that utilizes colloidal chitin as a substrate and produces chitin oligosaccharides. Further, we utilized Mucor circinelloides to produce bioethanol using the chitin oligosaccharides in the shake flask. We investigated the effect of inoculum age, filling volume, different substrates, and substrate concentration on bioethanol production using Mucor circinelloides from Bacillus haynesii-produced chitin oligosaccharides. Bacillus haynesii demonstrated a maximum chitinase activity of 3.08 U/mL with specific activity of 96 U/mg at the 90th h. Chitin oligosaccharides produced by Bacillus haynesii were confirmed using mass spectrometry. Bioethanol concentration was determined using dichromate oxidation assay as well as gas chromatography. The research resulted in 7.4 g/L of ethanol from 30 g/L of chitin oligosaccharides, with a maximum ethanol yield of 0.25 g of ethanol/g substrate at the 55th h with 48 h inoculum in 80 mL of fermentation medium. Results suggest that chitin oligosaccharides from Bacillus haynesii are an effective and renewable substrate for bioethanol production.

The potential of multistress tolerant yeast, Saccharomycodes ludwigii, for second-generation bioethanol production

Ethanol production at high temperatures using lignocellulosic biomass as feedstock requires a highly efficient thermo and lignocellulosic inhibitor-tolerant ethanologenic yeast. In this study, sixty-three yeast isolates were obtained from tropical acidic fruits using a selective acidified medium containing 80 mM glacial acetic acid. Twenty-nine of the yeast isolates exhibited significant thermo and acetic acid-tolerant fermentative abilities. All these isolates were classified into three major yeast species, namely Saccharomycodes ludwigii, Pichia kudriavzevii, and P. manshurica, based on molecular identification. Saccharomycodes ludwigii APRE2 displayed an ability to grow at high temperatures of up to 43 °C and exhibited significant multistress tolerance toward acetic acid, furfural, 5-hydroxymethyl furfural (5-HMF), and ethanol among the isolated yeast species. It can produce a maximum ethanol concentration of 63.07 g/L and productivity of 1.31 g/L.h in yeast extract malt extract (YM) medium containing 160 g/L glucose and supplemented with 80 mM acetic acid and 15 mM furfural as a cocktail inhibitor. When an acid-pretreated pineapple waste hydrolysate (PWH) containing approximately 106 g/L total sugars, 131 mM acetic acid, and 3.95 mM furfural was used as a feedstock, 38.02 g/L and 1.58 g/L.h of ethanol concentration and productivity, respectively, were achieved. Based on the results of the current study, the new thermo and acetic acid-tolerant yeast S. ludwigii APRE2 exhibited excellent potential for second-generation bioethanol production at high temperatures.

Production of second-generation bioethanol in the Russian Federation in the context of global trends

Aim. The presented study aims to identify trends in the production and use of second-generation bioethanol in foreign countries and to assess the potential for the development of production and use of second-generation bioethanol in the Russian Federation.Tasks. The author describes the current level of development of the global biofuel industry; identifies the specific features of the production and use of second-generation bioethanol in foreign countries; summarizes the experience of government support for the production and use of second-generation bioethanol in foreign countries; analyzes the current level and development potential of bioethanol production in Russia.Methods. This study uses the methods of system analysis and comparative analysis, as well as statistical, mathematical, and graphical methods of providing information.Results. Current production volumes of second-generation bioethanol in the world and in Russia are assessed; the peculiarities of government regulation of the production and use of secondgeneration bioethanol in the European Union (EU), Brazil, the US, and China are identified; the economic efficiency of gasoline and second-generation bioethanol production in Russia is compared; recommendations on the use of government support measures in the Russian biofuel industry are formulated.Conclusions. Even though global production and use of second-generation bioethanol currently amounts to a total of 65–125 million liters, mechanisms of government support for this area are systematically applied in many countries. This is due to the desire to decarbonize the transport sector without adversely affecting food security and natural ecosystems. The development of the production and use of second-generation bioethanol in Russia requires similar mechanisms of government support, and it can be relevant in the context of the need to achieve goals in the field of reducing greenhouse gas emissions.

The characterisation of Wickerhamomyces anomalus M15, a highly tolerant yeast for bioethanol production using seaweed derived medium.

Advanced generation biofuels have potential for replacing fossil fuels as society moves forward into a net-zero carbon future. Marine biomass is a promising source of fermentable sugars for fermentative bioethanol production; however the medium derived from seaweed hydrolysis contains various inhibitors, such as salts that affected ethanol fermentation efficiency. In this study the stress tolerance of a marine yeast, Wickerhamomyces anomalus M15 was characterised. Specific growth rate analysis results showed that Wickerhamomyces anomalus M15 could tolerate up to 600 g/L glucose, 150 g/L xylose and 250 g/L ethanol, respectively. Using simulated concentrated seaweed hydrolysates, W. anomalus M15’s bioethanol production potential using macroalgae derived feedstocks was assessed, in which 5.8, 45.0, and 19.9 g/L ethanol was produced from brown (Laminaria digitata), green (Ulva linza) and red seaweed (Porphyra umbilicalis) based media. The fermentation of actual Ulva spp. hydrolysate harvested from United Kingdom shores resulted in a relatively low ethanol concentration (15.5 g/L) due to challenges that arose from concentrating the seaweed hydrolysate. However, fed-batch fermentation using simulated concentrated green seaweed hydrolysate achieved a concentration of 73 g/L ethanol in fermentations using both seawater and reverse osmosis water. Further fermentations conducted with an adaptive strain W. anomalus M15-500A showed improved bioethanol production of 92.7 g/L ethanol from 200 g/L glucose and reduced lag time from 93 h to 24 h in fermentation with an initial glucose concentration of 500 g/L. The results indicated that strains W. anomalus M15 and W. anomalus M15-500A have great potential for industrial bioethanol production using marine biomass derived feedstocks. It also suggested that if a concentrated high sugar content seaweed hydrolysate could be obtained, the bioethanol concentration could achieve 90 g/L or above, exceeding the minimum industrial production threshold.

Second-generation bioethanol production from phytomass after phytoremediation using recombinant bacteria-yeast co-culture

• P. vittata phytomass can be a promising feedstock for bioethanol production. • Shaking with 1% HNO 3 pretreatment removed greater than 80% As from P. vittata phytomass. • Recombinant bacteria-yeast co-culture system resulted in 48.5% bioethanol yield. • Developed microbial system has a great potential for bioethanol production via CBP. Sustainable management of harvested hyperaccumulating plants used in phytoremediation of toxic metals is considered quite challenging. The biomass of hyperaccumulators can be an attractive feedstock for bioethanol production, while removal of toxic metals and efficient ethanol conversion systems are necessary to ensure safe and optimum bioethanol production. This study aimed to develop a compatible and efficient consolidated bioprocessing system (CBP) to produce bioethanol from phytomass of arsenic (As)-hyperaccumulator Pteris vittata . A recombinant kefir yeast Kluyveromyces marxianus (KR7 strain) contained six cellulase genes and two recombinant Bacillus subtilis (Type 1 and Type 2 strains) carrying cellulosomal genes in different arrangements were used, and the saccharification and fermentation of P. vittata phytomass were investigated through one-step (KR7 strain only) and co-culture ( B. subtilis + KR7 strain) methods. The results of reducing sugar showed that KR7 strain possesses higher saccharification ability than both B. subtilis strains. While the co-culture of B. subtilis Type 2 strain with KR7 strain gave the highest ethanol yield, which achieved 48.5% ethanol yield from P. vittata phytomass after 3 d cultivation. In addition, simple pretreatment by shaking P. vittata with 1% of HNO 3 efficiently removed more than 80% of As from the phytomass, suggesting its applicability and feasibility for efficient As extraction to ensure efficient and non-toxic ethanol production. Our results confirm that the developed recombinant bacteria-yeast co-culture possesses a great potential for optimum bioethanol production from As-hyperaccumulators-derived phytomass via CBP.