Potential For Bioethanol Production Research Articles

Evaluation of Ultrasound Waves on S. cerevisiae Stimulation in the Bioethanol Production from Rice Bran

The ultrasound exposure can affect the Saccharomyces cerevisiae growth and metabolic product generation. This study evaluated the effect of ultrasound on S. cerevisiae stimulation in lag and exponential phase cultured in defatted rice bran (DRB) employing a full-factorial design. Firstly, the DRB was hydrolyzed by protease, α-amylase, and amyloglucosidase; the hydrolyzed DRB (HDRB; 30 g L−1) was used as substrate for S. cerevisiae. The variables ultrasound power (132 to 330 W) and duty cycle (25 to 50%) were evaluated considering the temperature (30 °C), ultrasound frequency (37 kHz), and ultrasound exposure time (15 min) as fixed variables. The responses variables were the bioethanol productivity, cell productivity, cell number, cell viability, and efficiency (conversion yield of sugars into ethanol). A control treatment was performed in parallel. The application of ultrasound at a duty cycle of 50% stimulated cellular metabolism of S. cerevisiae both in lag and exponential phase, evidenced by the faster consumption of reducing sugars, bioethanol production, and biomass improvement. However, at the exponential phase, the ultrasound exposure was more promising due to the increased bioethanol productivity (up to 1.55 after ultrasound and 2.42 g L−1 h−1 at final fermentation process), cellular productivity (up to 0.93 g L−1 h−1), and efficiency (up to 103.17%). Around 60% of the total bioethanol was produced after ultrasound exposure in the exponential phase. The HDRB is a rice byproduct with a great potential for bioethanol production by S. cerevisiae ultrasound assisted, and the optimized process condition was achieved under ultrasound power of 132 W at duty cycle of 50%, applied in the exponential phase of yeast growth curve.

ADANA KOŞULLARINDA TATLI SORGUMUN BİYOKÜTLE VE BİYOETANOL POTANSİYELENİN BELİRLE

The research was carried out to determine the potential of biomass and bio-ethanol production of different sweet sorghum genotypes under Adana Conditions. Twenty-one sweet sorghum genotypes obtained from domestic and foreign sources were used experimental material. The field experiment was conducted in the experimental area of the Eastern Mediterranean Agricultural Research Institute, Adana -Turkey in second crop condition in 2016 and 2017. Each genotype was sown in 4 rows with 5 m length and 0.7 m apart according to randomized complete block design with four replications. In the research, agronomic traits were determined on 10 randomly selected plants of each genotype. According to the two years averaged values, days after sowing, plant height, biomass yield, stalk yield, juice yield, brix, and theoretical ethanol yield ranged from 98.1 to134.4 days, 232.2 to 429.3 cm, 83.4 to 214.9 t ha-1, 69 to 183 t ha-1, 23 to 63 m3 ha-1, 15.50 to 20.00 %, and 2020 to 5300 L ha-1, respectively. From the results of the research, it was concluded that sweet sorghum could be successfully grown for biomass or bio-ethanol production as second crop under Adana Conditions.

Comparison of Conventional and Novel Pre-treatment Methods for Bioethanol Production from Fruit and Vegetable Wastes

In this study, novel and conventional techniques for the production of bioethanol from fruit and vegetable wastes (FVWs) by yeast and bacterial fermentation were investigated experimentally. Different pretreatment techniques (acid, heat, acid/heat, and microwave) for yeast fermentation were compared. Maximum ethanol concentrations of 11.7 and 11.8 g L–1 were observed from acid/heat and microwave pretreatment, respectively, by using Saccharomyces cerevisiae. On the other hand, biochar production from FVWs and syngas fermentation from the waste gas of this process were integrated. From waste gas with 12 % CO content, 5.5 g L–1 and 2.5 g L–1 ethanol production was observed by using anaerobic mixed culture and Clostridium ljungdahlii, respectively. The overall results emphasize the potential of bioethanol production from FVWs by economically feasible and environmentally friendly methods.

Temperature profiled simultaneous saccharification and co-fermentation of corn stover increases ethanol production at high solid loading

Trade-off temperature used in traditional SScF process always resulted in inhibition on enzymatic hydrolysis (low temperature inhibition, LTI). Thus, effect of temperature and solid loading on LTI was investigated in this study. Results showed that LTI was more severe at lower temperature and higher solid loading. Accordingly, a novel temperature profiled SScF process was designed. Two specific yeast strains, high temperature resistant Saccharomyces cerevisiae and xylose utilizing S. cerevisiae were co-cultured in the novel SScF process. Through eliminating sugars accumulation and alleviating ethanol repression by process optimization, 59.8 g/L ethanol was achieved in temperature profiled SScF at 12% glucan loading. Cell viability of yeast in co-culture SScF was ten times, sometimes even thousands of times, of that in mono-culture SScF during the late phase of the fermentation (48–108 h). It suggested that high temperature resistant strain helped the xylose utilizing strain maintain cell viability in SScF at high temperature (42 ℃). Based on the results, the designed novel temperature profiled SScF process showed appealing potential for bioethanol production at high solid loading and high temperature.

Determination of bioethanol production potential from lignocellulosic biomass using novel Cel-5m isolated from cow rumen metagenome

We are reporting the novel cellulase named Cel-5M from rumen metagenome. The deduced amino acid sequence and biochemical characterization suggested that Cel-5M is endoglucanase from the GH5 family with multifunctional potential. Cel-5M showed similarity to non-characterized proteins and the genus Prevotella as parental organism. The 957 bp ORF encoding Cel-5M was cloned and overexpressed in E. coli and purified. The recombinant Cel-5M showed maximum activity at pH 6.0 and 40 °C. It retained more than 80% activity between 4 and 7 pH and 65% thermostability between 30 and 70 °C. Cel-5M showed activity on various substrates like CMC, Filter paper, Avicel, Xylan, β-Mannan, and Glucopyranoside, which confirmed its multifunctional characteristics and classifies as member of subfamily 4 of GH5 (GH5_4). LCB hydrolysis potential of Cel-5M was studied using wheat straw (10% w/v). Alkali-treated and steam-exploded wheat straws were inoculated with 1 mg/g Cel-5M, 2% yeast in a reaction mixture and SSF at 10% w/v loading rate. The ethanol yield 0.46 g/g and 0.43 g/g of cellulose obtained after 72 h fermentation in alkali-treated and steam-exploded wheat straw, respectively. Cel-5M is novel multifunction cellulase belongs GH-5 endoglucanase from rumen origin can be employed for bioethanol based biofuel production.

Potential of bioethanol production from biomass of various Miscanthus genotypes cultivated in three-year plantations in west-central Poland

Production of bioethanol from Miscanthus biomass has been studied for years, yet many important aspects still remain to be evaluated and optimised. It may be assumed that the three-year yield-building phase of Miscanthus growth would be sufficient for stabilisation of biomass composition to provide suitable biomass as a bioethanol feedstock. Such early biomass harvesting could be important for the economics of newly established plantations. This study shows the gradual stabilisation of biomass production by genotypes of M. × giganteus, M. sinensis and M. sacchariflorus within the first three years of cultivation on moderately fertile soil, under the climatic conditions of west-central Poland. Photosynthesis, plant growth, biomass yield, and biochemical and elemental composition, simultaneously stabilised. The tested genotypes differed in their photosynthesis intensity and yield traits. There was little variation in the biochemical composition among genotypes; in comparison to Miscanthus cultivated in a more oceanic climate there was lower cellulose content, but higher lignin content. Aside from basal elements, the tested genotypes varied considerably in their accumulation of most macro- and especially microelements. The three-year old, winter-harvested technical biomass was used for pilot-scale bioethanol production including alkaline delignification and SSF technology. The particular biochemical components and elements in the biomass differently impacted the production process, yet for most genotypes the bioethanol produced was highly correlated with the cellulose:lignin ratio. The highest yield (g/kg DM) and efficiency (%) of raw bioethanol production were recorded for genotypes of M. sinensis (234–253 g/kg DM, 83–86%), followed by M. sacchariflorus (207–237 g/kg DM, 76–81%) and M. × giganteus (185–222 g/kg DM, 62–76%). However, biomass yield had a substantial effect on the estimated bioethanol production. The study pointed to the high potential for raw bioethanol production (4,400-5,600 L/ha) exploiting 3-year Miscanthus plantations, comparably for M. × giganteus and M. sinensis cultivated in a temperate transitional climate.

High-Throughput Phenotyping of Bioethanol Potential in Cereals Using UAV-Based Multi-Spectral Imagery.

Bioethanol production obtained from cereal straw has aroused great interest in recent years, which has led to the development of breeding programs to improve the quality of lignocellulosic material in terms of the biomass and sugar content. This process requires the analysis of genotype–phenotype relationships, and although genotyping tools are very advanced, phenotypic tools are not usually capable of satisfying the massive evaluation that is required to identify potential characters for bioethanol production in field trials. However, unmanned aerial vehicle (UAV) platforms have demonstrated their capacity for efficient and non-destructive acquisition of crop data with an application in high-throughput phenotyping. This work shows the first evaluation of UAV-based multi-spectral images for estimating bioethanol-related variables (total biomass dry weight, sugar release, and theoretical ethanol yield) of several accessions of wheat, barley, and triticale (234 cereal plots). The full procedure involved several stages: (1) the acquisition of multi-temporal UAV images by a six-band camera along different crop phenology stages (94, 104, 119, 130, 143, 161, and 175 days after sowing), (2) the generation of ortho-mosaicked images of the full field experiment, (3) the image analysis with an object-based (OBIA) algorithm and the calculation of vegetation indices (VIs), (4) the statistical analysis of spectral data and bioethanol-related variables to predict a UAV-based ranking of cereal accessions in terms of theoretical ethanol yield. The UAV-based system captured the high variability observed in the field trials over time. Three VIs created with visible wavebands and four VIs that incorporated the near-infrared (NIR) waveband were studied, obtaining that the NIR-based VIs were the best at estimating the crop biomass, while the visible-based VIs were suitable for estimating crop sugar release. The temporal factor was very helpful in achieving better estimations. The results that were obtained from single dates [i.e., temporal scenario 1 (TS-1)] were always less accurate for estimating the sugar release than those obtained in TS-2 (i.e., averaging the values of each VI obtained during plant anthesis) and less accurate for estimating the crop biomass and theoretical ethanol yield than those obtained in TS-3 (i.e., averaging the values of each VI obtained during full crop development). The highest correlation to theoretical ethanol yield was obtained with the normalized difference vegetation index (R2 = 0.66), which allowed to rank the cereal accessions in terms of potential for bioethanol production.

Using C4 perennial rangeland grasses for bioenergy

The aim of this paper was to determine the potential of bioethanol production using two rangeland communities dominated by Spartina argentinensis Parodi or Panicum prionitis Ness. and its environmental sustainability, considering soil organic carbon and biodiversity measured in two taxa: flowering plants and epigeal soil arthropods. S. argentinensis and P. prionitis biomass production with two different harvest frequencies (every 6 or 12 months) was estimated and compared with control areas. Biomass production did not differ with harvest frequency. Although cell wall fibers composition varied with species and treatment, potential bioethanol production per hectare was not affected and yields were similar to those obtained from other lignocellulosic materials reported in the literature. According to our results, one annual harvest is recommended for both plant communities in order to minimize economic and energy costs. Soil organic carbon showed no statistically significant differences due to treatments in the S. argentinensis community, though differences were found in the middle layer (7.5–15 cm) of the P. prionitis rangeland. The vegetation and arthropods biodiversity indices analyzed (richness, evenness, abundance, and diversity) were not affected by treatments.

Bioethanol production potential in Bangladesh from wild date palm (Phoenix sylvestris Roxb.): An experimental proof

To sustain economic growth in Bangladesh, energy demand is expected to increase rapidly, resulting in more greenhouse gas emissions, as the energy sector, including transport and electricity, is dominated by fossil fuels. In order to reduce these emissions, the government of Bangladesh has already formed a long-term energy plan, part of which is introducing a 5% blend of bioethanol with gasoline in the transport sector. However, the source of this bioethanol has not yet been identified. An investigation has thus been conducted to evaluate the potential of bioethanol production using wild date palm fruit pulp and sap, sugary biomass of a perennially grown plant in Bangladesh that has been grown for decades without regular agronomic practice. A male plant produced 140.42 kg sugary biomass per year with 29.85% total sugar whereas a female plant yielded 195.56 kg, containing an average of 43.61% of total sugar. A batch fermentation study using Saccharomyces cerevisiae found that fruit pulp extract and sap could be conveniently fermented without nutritional supplementation to potentially yield ethanol. An average of 0.278 g/g ethanol was yielded from the fruit pulp extract and sap fermentation. From these findings, it was estimated that minimum 8076.62 L of ethanol could be obtained from an orchard comprising 500 plants per hectare with the planting ratio of male: female plants of 1:4. This indicates that this biomass of the wild date palm is a highly promising sugary feedstock for the potential production of bioethanol.

Optimization of Acid and Steam Explosion Pretreatment of Cogon Grass for Improved Cellulose Enzymatic Saccharification

Acid-impregnation and its combination with steam explosion were evaluated and optimized using Response Surface Methodology. At 10% solid-liquid ratio, cogon was impregnated with diluted H2SO4 solution (0 to 3%, w/w) at different ranges of temperature (40 to 120 °C) and varied time (0 to 130 min). Impregnated samples were then subjected to enzymatic saccharification using 60 FPU/g Accelerase 1500™. After enzymatic saccharification, the concentration of reducing sugar released was measured using Dinitrosalicylic (DNS) Colorimetric Method. Based on the results, Response Surface Model (RSM) showed that the optimum condition, predicting 7.18% Reducing Sugar Yield (RSY), was impregnation of cogon using 1.9% H2SO4 at 91.8 °C for 56 min. Experimental verification of optimum condition, done in triplicates, showed 6.35 + 0.05% RSY. Acid-impregnated cogon was subjected to steam explosion to improve saccharifiability. Factors varied were temperature (137 to 222 °C) and exposure time (17 to 582 s). Steam-exploded samples were saccharified and RSY was determined. RSM indicated that the best steam explosion condition, predicting 7.91% RSY, was 179 °C and 500 s. Experimental verification of optimum condition showed 8.78 + 0.02% RSY. Using RSY as basis, steam explosion improved saccharifiability of H2SO4-impregnated cogon by 38%, thus, increasing production of reducing sugars for potential bioethanol production.

Biomass yield, chemical composition and theoretical ethanol yield for different genotypes of energy sorghum cultivated on marginal land in China

Energy sorghum [Sorghum bicolor (L). Moench] is potentially of great significance for bioethanol production because of its high biomass and wide adaptability. In this study, a field experiment was conducted on a semiarid marginal land in Inner Mongolia (39°10′N, 109°53′E), China, to assess the effects of genotypes with similar growth duration and biomass yield levels on chemical composition and theoretical ethanol yield (TEY) in both leaves and stems of four genotypes each of sweet and biomass sorghum in 2013 and 2014. Among all varieties, no significant variation was observed in the biomass yield of leaf (1.81–2.55 Mg ha−1) and stem (3.73–4.87 Mg ha−1), which was relatively low due to the marginal land with low temperature conditions. By contrast, considerable variation was detected in soluble sugars, ash and hexose contents of leaves and stems among the sweet sorghum varieties over two years. Compared with the sweet type, biomass sorghum varieties exhibited significantly lower soluble sugars content but higher cellulose, hemicellulose, and lignin contents in both leaf and stem tissues, resulting in significantly lower hexose and higher pentose contents. Moreover, stems exhibited significantly higher total content of hexose and pentose (725.4 g kg−1) than leaves (642.3 g kg−1) across all varieties, leading to significantly higher TEY of stems than that of leaves. Despite the slightly higher TEY of sweet sorghum, biomass sorghum varieties exhibited particularly stable chemical components and TEY across both experimental years, resulting in greater potential for industrial bioethanol production in this study. Overall, varietal selection was effective in improving the biomass feedstock quality of energy sorghum for biochemical conversion. The findings of this study will help to facilitate industrial bioethanol production from dedicated bioenergy crops.

Wheat straw, corn stover, sugarcane, and Agave biomasses: chemical properties, availability, and cellulosic‐bioethanol production potential in Mexico

AbstractMexico is one of the largest agricultural producers in Latin America and generates a large amount of agricultural residue. The aim of this study was to establish the usefulness of four of the main Mexican crops (corn, wheat, sugarcane, and Agave) as feedstock for lignocellulosic bioethanol production. The lignocellulosic residue ratio (RR), defined as weight of residue (in tons) per ton of product, was measured by sampling crop fields in 11 geographic regions of Mexico. The chemical composition, assessed by Fourier‐transform infrared spectroscopy (FTIR) and carbon‐13 nuclear magnetic resonance (13C NMR), and structural composition (extractives, cellulose, hemicellulose, and lignin contents), heating value, and metal content of these lignocellulosic residues were measured. Biorefinery locations, and their theoretical bioethanol production, were suggested using the gravity center method and techno‐economic criteria. The highest RR (1.1 ton of straw per ton of grain) was obtained for wheat straw followed by corn (0.8 ton of stover per ton of grain), sugar cane (0.15 ton of bagasse per ton of cane), and Agave (0.2 ton of bagasse per ton of stem). The composition of these biomasses varied significantly depending on the parental material in extractive compounds, lignocellulosic matter, ashes, hemicellulose, lignin, O‐alkyl C, aromatic C, and carboxyl C. The cellulose crystallinity index and the heating value exhibited small variations among biomasses. Copper, Zn, Cd, and Ni content in the biomasses generally exceeded the European Norm (EN‐Plus FprEN 1496 1‐2 B) for solid biofuels. In total, these agricultural biomasses could be used as feedstock for 34 biorefineries in Mexico with a total bioethanol production potential of approximately 1246 million L year–1. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd

Isolation and characterization of thermotolerant yeasts for the production of second-generation bioethanol

The purpose of this study was to isolate, identify, and characterize the thermotolerant yeasts for use in high-temperature ethanol fermentation. Thermotolerant yeasts were isolated and screened from soil samples collected from the Mekong Delta, Vietnam, using the enrichment method. Classification and identification of the selected thermotolerant yeasts were performed using matrix-assisted laser desorption ionization/time-of-fight mass spectrometry (MALDI-TOF/MS) and nucleotide sequencing of the D1/D2 domain of the 26S rDNA and the internal transcribed spacer (ITS) 1 and 2 regions. The ethanol production by the selected thermotolerant yeast was carried out using pineapple waste hydrolysate (PWH) as feedstock. A total of 174 yeast isolates were obtained from 80 soil samples collected from 13 provinces in the Mekong Delta, Vietnam. Using MALDI-TOF/MS and nucleotide sequencing of the D1/D2 domain and the ITS 1 and 2 regions, six different yeast species were identified, including Meyerozyma caribbica, Saccharomyces cerevisiae, Candida tropicalis, Torulaspora globosa, Pichia manshurica, and Pichia kudriavzevii. Among the isolated thermotolerant yeasts, P. kudriavzevii CM4.2 displayed great potential for high-temperature ethanol fermentation. The maximum ethanol concentration (36.91 g/L) and volumetric ethanol productivity (4.10 g/L h) produced at 45 °C by P. kudriavzevii CM4.2 were achieved using PWH containing 103.08 g/L of total sugars as a feedstock. These findings clearly demonstrate that the newly isolated thermotolerant yeast P. kudriavzevii CM4.2 has a high potential for second-generation bioethanol production at high temperature.

Experimental characterization of selected Nigerian lignocellulosic biomasses in bioethanol production

Experimental characterisation of five biomass wastes: corn cobs, cassava peels, rice husks, white yam peels and sugar cane bagasse based on proximate analysis and X-ray diffraction (XRD) analysis has been reported in this study due to their huge inherent potential for bioethanol production. XRD gave an indication of the presence of cellulose and carbon in the biomasses. Thermo-gravimetric analysis showed that the cellulose composition of the five biomasses is quite close, with sugar cane bagasse having the highest content of 39.8 wt % and cassava peels biomass presented the lowest content of 25.8 wt %. For each of the biomasses presented in this study, their cellulose content is in conformity with reported values from previous work on them. The results demonstrate that the collected lignocellulosic biomasses are a potential substrate for energy and bioethanol production which can constitute a huge market as the biomasses are sustainably produced as wastes in Nigeria.

Potential bioethanol production from sweet sorghum on marginal land in China

Sweet sorghum is one of the best renewable non-grain energy crops for ethanol production due to its high sugar content, short growing period and good tolerance to natural conditions. However, insufficient studies have been conducted on the spatial distribution of sweet sorghum-based bioethanol production potential. This study presents a method, i.e., a land surface process model (Environmental Policy Integrated Climate GIS-based (GEPIC) model) coupled with a life cycle analysis (LCA), to simulate the spatial distribution of potential bioethanol production, energy efficiency and environmental impacts throughout the whole life cycle of sweet sorghum-based ethanol. The results showed that approximately 49.65 million ha of marginal land in China were suitable for sweet sorghum planting, and more than 13.57 million tons of sweet sorghum could be yielded. Based on sweet sorghum, 847.81 thousand tons of ethanol could be produced. A potential net energy gain of 115 billion MJ which is equivalent to 2.38 million tons of 90-octane gasoline would be achieved if all marginal lands could be used. The results of the environmental impact assessment showed that the total environmental effect index was 0.25 million (population equivalents). The global warming potential was the most significant environmental impact category. Guizhou Province can be given priority for sweet sorghum-based bioethanol development in China.

Evaluation and characterization of novel sources of sustainable lignocellulosic residues for bioethanol production using ultrasound-assisted alkaline pre-treatment

In recent years, research is focused on finding a sustainable and eco-friendly lignocellulosic biomass for the effective production of bioethanol to meet the world’s energy demand. The present study investigates the bioethanol production potential of four different lignocellulosic biomass residues viz., Saccharum arundinaceum (hardy sugar cane), Arundo donax (giant reed), Typha angustifolia (narrow-leaved cattail), and Ipomoea carnea (pink morning glory). The maximum reducing sugar release showed 185.00 ± 1.57, 213.73 ± 3.47, 187.57 ± 2.14, 294.08 ± 3.98 mg/g and fermentation efficiency of 72.60 ± 8.17%, 82.59 ± 7.42%, 77.45 ± 7.35%, and 85.04 ± 8.37% which was analyzed by estimating the percentage of bioethanol yield were achieved for Saccharum arundinaceum, Arundo donax, Typha angustifolia, and Ipomoea carnea, respectively. The chemical composition of biomass was characterized using National Renewable Energy Limited (NREL) protocol. The effect of ultrasound (US)-assisted alkaline pre-treatment on the four biomasses was characterized by different techniques. The cavitation phenomena of US-assisted alkaline pre-treatment was evident from the decreased value of lignin percentage, increased surface porosity and area, changes in crystallinity index (CrI) values and in the functional groups of biomass. The results revealed that all the four lignocellulosic biomass residues could be utilized as an effective and sustainable source for the production of bioethanol using US-assisted sodium hydroxide as a pre-treatment tool.

Preliminary Assessment for the Potential of Citrus Limetta Peel Waste for Bioethanol Production under Indian Conditions

Brazil is the top producer of citrus fruits in the world with 20 million tons annually while India stands 5th on the list with total production of 6,286,000 tonnes annually. Citrus limetta being the third most cultivated species of citrus after orange and lemon with 4,200,000 metric tonnes produce annually in the world. CLPW is pectin rich agro waste and can utilised for the production of bioethanol which can be used as a substitute for the conventional fuel as it is cleaner and cheaper fuel source. On overviewing different research work it can be concluded that fruit peel waste especially citrus fruit has a huge potential for bioethanol production rather discarded into the environment. The carbohydrates content of the solid waste can be determined by using Anthrone method. The fermentation is done in the bioreactor using the combination with the maximum reducing sugar yield and using S. cerevisiae as the microorganism. Dichromate method used for the analysis of ethanol production. The moisture content of waste was 80.59% of total weight. The average carbohydrates content of sample was found out to be 62.35% on wet weight whereas the ash content was 10.51% on dry weight basis. With increase in acid concentration there is decrease in reducing sugar yield and vice-versa. With increase in temperature there is increase in reducing sugar yield. It can also be concluded that reducing sugar yield was maximum at 150˚C and without acid. It can be also concluded that rather throwing the peel waste it can be used as a source of energy production. It can be also concluded that the method used for treatment of waste can be serve as a tool for waste management.

Bioethanol and biomethane potential production of thirteen pluri-annual herbaceous species

The research aimed to study and characterize, in a four-year study, thirteen pluri-annual herbaceous species for their potential bioethanol and biomethane production. The highest biomass yield was obtained with Arundo donax followed by Miscanthus x giganteus. Biomass cellulose content had median values ranging from 23.1% (Symphytum x uplandicum) to 45.4% (Lythrum salicaria), hemicellulose from 9.4% (Iris pseudacorus) to 36.8% (Glyceria maxima) and lignin from 2.6% (G. maxima) to 14.5% (Helianthus tuberosus and L. salicaria). The best ethanol and methane median yields were achieved by A. donax (3.5 Mg ha−1 and 8227 m3 ha−1, respectively) followed by M. x giganteus (3.2 Mg ha−1 and 4446 m3 ha−1, respectively). Methane transformation showed a higher energy output than ethanol with values ranging from 1 GJ ha−1 (Phalaris arundinacea) to 508 GJ ha−1 (A. donax) and from 1 GJ ha−1 (P. arundinacea) to 624 GJ ha−1 (A. donax) for ethanol and methane, respectively. Results showed that A. donax and M. x giganteus are the most interesting species for bioethanol and biomethane production.

Harnessing the potential of bio‐ethanol production from lignocellulosic biomass in Nigeria – a review

AbstractThe need to diversify energy sources and to change from the present non‐renewable hydrocarbon sources to renewable energy sources has prompted huge investments in research activities to produce bioethanol from carbohydrate‐rich foodstuffs such as cassava tuber, sugarcane molasses, yam tubers, rice grains, corn grains, and a host of others. In recent times, however, more attention has been given to producing bioethanol from the non‐edible parts of carbohydrate‐rich foodstuffs, which are obtained mainly as waste products from food‐crop processing. Such non‐edible components include peels, bagasse, straw, stalk, and cobs. The most important component of the biomass is lignocellulose, which is broken down into carbohydrates and then fermented. The major challenge in deploying biomass as feedstock for bioethanol production is the fact that lignocellulosic biomass is highly recalcitrant and therefore requires more vigorous pretreatment prior to saccharification and fermentation. The main techniques used for pretreating lignocellulosic materials are physical and thermal as well as chemical and biological methods. In Nigeria, lignocellulosic bioethanol production potential from agricultural residues amounts to about 7.556 × 109 L per annum with more than 62% generated from process residues. Cassava biomass alone can produce more than 114 L of bioethanol for every ton of cassava peels after processing. Nigeria has more than enough agricultural residues for bioethanol production to meet its sustainable bioethanol‐blending demands. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.

Sugars Yield Obtained after Acid and Enzymatic Hydrolysis of Fast-growing Poplar Wood Species

The potential of fast-growing poplar species was evaluated for bioethanol production. The yields of glucose and xylose from acid and enzymatic hydrolysis were compared. The hydrolysis processes were performed on raw and extracted wood. The extracted wood was obtained by action of a chloroform and 96% ethanol (93:7 w/w) mixture. Additionally, to enhance the enzymatic hydrolysis efficiency, a liquid hot water (LHW) pretreatment was used. The acid hydrolysis turned out to be a good method to verify the biomass potential for bioethanol production. After acid hydrolysis of raw and extracted biomass, high total sugars yields were obtained (between 626.2 to 808.5 mg/g raw or extracted biomass), while in the case of enzymatic hydrolysis the total sugars yields were very low (between 45.5 to 68.9 mg/g raw or extracted biomass). The LHW pretreatment greatly enhanced the enzymatic digestibility of the studied wood. The average glucose yield from enzymatic hydrolysis was up to 602.0 mg/g pretreated biomass and was higher than that from acid hydrolysis (the maximum yield was 566.9 mg/g extracted biomass). As a result of the LHW pretreatment, up to 91.3% of the hemicelluloses were removed from the solid fraction. From the obtained glucose and xylose results, it was concluded that Populus trichocarpa wood had a higher potential for bioethanol production than P. deltoides x maximowiczii wood. The presence of extractives (low molecular substances) in raw poplar wood (up to 2.8%) had a low impact on the yield from acid and enzymatic hydrolysis.