Barley straw (Hordeum vulgare L.) is an attractive lignocellulosic material and is one of the most abundant renewable resources for fuel-ethanol production. Although it contains high cellulose and hemicellulose contents, it has several challenges and limitations in the process of converting barley straw (BS) to fuel-ethanol. High ash, silica, and lignin contents in barley straw make it an inferior feedstock for enzymatic hydrolysis. Pretreatment plays an important role for structural and compositional changes in increasing the efficiency of enzymatic hydrolysis and makes the whole process economically viable.
Waste money bills (WMB) is a by-product of the money making process that consists of rich-cellulosic material for many biotechnological applications. This waste money bills is unusable and usually exhausted. Saccharification was improved using various concentrations of sodium hydroxide, NaOH (0.0, 0.5, 1.0, 2.0, 2.5, and 3.0% v/v) and various reaction times (20, 30, and 40 min) during pretreatment at 121 °C. Prior to ethanol fermentation, the highest glucose yield (62.2 mg/mL) was found by pretreatment consisting of 30 min at 2.0% NaOH, and it increased 33.8% as compared to an untreated sample. The highest amount of ethanol was obtained (26.1 mg/mL) during fermentation, and this was increased 95.3 and 22.5% as compared to aerobic and anaerobic conditions respectively during pretreatment with 2.0% NaOH for 30 min. Under anaerobic conditions, ethanol fermentation was enhanced by adding 0.4 mmol benzoic acid. Production of ethanol from waste money bills would cut waste management costs and make profitable.
Waste money bills (WMB) that are no longer legal tender are nonrecyclable and are generally useless. In this work, we used this cellulose-rich material for ethanol fermentation for the first time. Torrefaction of this nonlignocellulosic waste material was attempted to examine whether such material could benefit from this process as a conventional lignocellulosic material does. Effects of two important parameters, that is, residence times (20, 40, and 60 Min) and temperatures (140, 160, 180, 200, and 220°C), on the torrefaction yield were studied under an inert atmosphere. Glucose and ethanol yields were compared using a factorial experimental design. The highest glucose yield (81.59 mg/mL) was obtained with a torrefaction treatment consisting of 40 min at 180 °C, and it was increased 44.89% compared to untreated WMB. Based on ethanol feasibility studies conducted on WMB, this estimated quantity of glucose could be produced for subsequent fermentation to ethanol (38.92 mg/mL) and it was increased 47.92% compared to the untreated sample. The fermentation rate was also enhanced by adding 0.4 mM benzoic acid under anaerobic conditions. It is concluded that production of ethanol from WMB would reduce waste management costs and thus would be profitable.
Rice straw is an attractive lignocellulosic material for ethanol production, since it is one of the most abundant renewable resources. It generally has high cellulose and hemicellulose contents that can be readily hydrolysed into sugars for subsequent ethanol fermentation. The pretreatment method plays an important role in increasing the efficiency of enzymatic saccharification, thereby making the whole process economically viable. Torrefaction is an appropriate pretreatment technique for enhancing the enzymatic reaction and subsequent ethanol production.
Cellulase-free xylanase has potential for its application in the selective removal of hemicellulose from kraft pulp to give good strength to paper. In this study, a gene (xyn) encoding cellulase activity-free xylanase enzyme (Xyn) was isolated from Paenibacillus polymyxa PPL-3. The xyn gene encoded a protein of 221 amino acids, and the purified Xyn was about 22.5 kDa measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Moreover, the cellulase activity-free xylanase enzyme (Xyn) was displayed on the cell surface of Saccharomyces cerevisiae EBY100 using Aga2p as an anchor protein. Cell surface display of xylanase enzyme (Xyn) on S. cerevisiae EBY100 was confirmed by immunofluorescence microscopy. Optimum cell surface display of xylanase enzyme (Xyn) was observed at pH 7 and 40 °C. Therefore, cell surface-displayed xylanase enzyme (Xyn) can be used in the paper industry.
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