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Factors Responsible for Spatial Distribution of in Soil
Published in Suhaib A. Bandh, Javid A. Parray, Nowsheen Shameem, Climate Change and Microbial Diversity, 2023
Cellulose, the most abundant polysaccharide present in the cell walls of plants that represents a significant contribution to the soil. Cellulase is an enzyme which acts on cellulose polymer. Cellulose on earth occurs abundantly in the form of wood, chips, and municipal waste. This enzyme activity is extensively studied in plant litters. During litter decomposition, soil microbes discharge cellulose as extracellular enzyme. Several external factors like temperature, moisture, pH, and cellulose concentration influence the cellulase activity in litter decomposition (Raju et al., 2016). Cellulase is a core enzyme consists of endo, exo, and ß-glucosidase. Endo-β-1,4-glucanase hydrolyzes 1,4-β-glycosidic bonds in cellulose, lichenin, and β-D glucan in cereals. Exo-β-1,4-glucanase hydrolyzes 1,3-β-D glycosidic linkages in arabinogalactan. β-Dglucosidase hydrolyzes terminal nonreducing β-D glucose which releases terminal glucose step-by-step (Raju et al., 2016).
Nature’s Green Catalyst for Environmental Remediation, Clean Energy Production, and Sustainable Development
Published in Miguel A. Esteso, Ana Cristina Faria Ribeiro, A. K. Haghi, Chemistry and Chemical Engineering for Sustainable Development, 2020
Benny Thomas, Divya Mathew, K. S. Devaky
Cellulases are the key enzymes for the degradation of cellulose, the most abundant biopolymer found on the earth.43 Cellulases are generally produced by microorganisms.44 They may be cell-bound, associated with cell envelope, and extracellular. Usually, cellulases are composed of a mixture of several enzymes such as endoglucanase and exoglucanase or cellobiohydrolase.45 The endoglucanase attacks regions of low crystallinity in the cellulose fiber and creates free chain ends. But the exoglucanase removes cellobiose units from the free chain ends of cellulose and degrades it. The enzyme action of β-glucosidase is helpful for the hydrolysis of cellobiose to glucose units. Cellulases are useful in the detergent and washing powders manufacturing industries, where cellulose microfibrils produced during processes are removed by these enzymes.46 Alkaline cellulases can be employed for the bioremediation of ink in paper and pulp industry during the recycling of paper and waste management.47,48 Cellulase can adapt to harsh environmental conditions like extreme pH and temperature.
Nanobiotechnology of Ligninolytic and Cellulolytic Enzymes for Enhanced Bioethanol Production
Published in Madan L. Verma, Nanobiotechnology for Sustainable Bioenergy and Biofuel Production, 2020
Pardeep Kaur, Gurvinder Singh Kocher
Cellulase can be produced via biological route using bacterial or fungal fermentation. There is a wide range of microorganisms, capable of producing cellulases such as aerobic and anaerobic bacteria, soft rot fungi, white rot fungi (WRF) and brown rot fungi (BRF). Bacteria belonging to genera of Clostridium, Cellulomonas, Bacillus, Thermomonospora, Ruminococcus, Bacteriodes, Erwinia, Acetovibrio, Microbispora and Streptomyces are known to produce cellulose (Bisaria 1998). Anaerobic bacterial species such as Clostridium phytofermentans, Clostridium thermocellum, Clostridium hungatei and Clostridium papyrosolvens produces cellulases with high specific activity (Duff and Murray 1996, Bisaria 1998). Most of the fungi can produce a complete cellulase system as compared to bacteria. The commercial cellulase is most commonly produced from two strains of soft rot fungi (SRF), namely Trichoderma reesei and Aspergillus niger (Kaur et al. 2007). Fungi known to produce cellulases include Sclerotium rolfsii, Phanerochaete chrysosporium and various species of Trichoderma, Aspergillus, Schizophyllum and Penicillium (Fan et al. 1987, Duff and Murray 1996).
Lignocellulosic bioethanol production using Neurospora intermedia in consolidated bioprocessing (CBP) system
Published in Biofuels, 2023
Elvi Restiawaty, Arinta Dewi, Tareqh Al Syifa Elgi Wibisono, Yogi Wibisono Budhi
Figure 8 shows the concentrations of bioethanol, glucose, and acetic acid. Cellulase enzyme activity was optimal at 45–50 °C, and the glucose concentration increased from 0.061 g/L to 0.127 (45 °C) and 0.372 (50 °C) after 48 h. Low glucose availability likely influenced the decline due to low cellulose and hemicellulose hydrolysis levels. Neurospora possesses the ADH1 alcohol dehydrogenase gene 1 and ADH3 (alcohol dehydrogenase 3) to synthesize the enzyme alcohol dehydrogenase, a key enzyme in the production and use of alcohol (bioethanol). These enzymes can catalyze carboxylic ester formation from alcohols and aldehydes, such as acetic acid [33]. This ester formation was evidenced by acetic acid, as shown in Figure 8, which illustrates the reduction of bioethanol in line with increased acetic acid concentrations [74]. At 40 °C, the levels of bioethanol and acetic acid decreased. This situation likely occurred because bioethanol was converted into acetic acid, then to acetyl Co-A, and entered the TCA cycle, as evidenced by the formation of citric acid observed by HPLC analysis. Meanwhile, to improve the formation of bioethanol at 45–50 °C, the activity of hydrolytic enzymes was elevated with increased temperature so that the rate of glucose formation increased. A high temperature of 50 °C would not be profitable for bioethanol production, but it was beneficial to increasing cellulase activity.
Digestibility of Bacillus firmus K-1 pretreated rice straw by different commercial cellulase cocktails
Published in Preparative Biochemistry & Biotechnology, 2022
Thitiporn Teeravivattanakit, Sirilak Baramee, Prattana Ketbot, Rattiya Waeonukul, Patthra Pason, Chakrit Tachaapaikoon, Khanok Ratanakhanokchai, Paripok Phitsuwan
Lignocellulosic material is an important renewable feedstock for the sustainable production of biofuels and biochemicals. Rice straw, a residue after rice grain collection, is an abundantly available lignocellulosic material, particularly in Asia countries.[1] It is estimated that rice straw's annual production is approximately 740.95–1111.42 million tons worldwide.[1] This vast amount makes rice straw an attractive feedstock for the production of biofuels and biochemicals. Rice straw contains cellulose (34–43%), hemicellulose (mainly xylan, 19–22%), and lignin (13–22%).[2] These chemical components are present in the plant cell walls. Cellulose is a source of glucose, and hydrolysis of cellulose by cellulase enzymes is a good means to produce glucose for microbial fermentation.[1] However, cellulose is embedded in a layer of hemicellulose and lignin. Thus, the cellulose-hemicellulose-lignin networks should be disrupted to make cellulose accessible to cellulases.
Comparing bioethanol production using buttonwood (Conocarpus erectus) and date palm (Phoenix dactylifera) leaves as raw material
Published in Biofuels, 2021
Mohamed A. Gomaa, Moza Al-Makhmari, Mohab Ali Al-Hinai
Production of cellulase from the 4 isolated Bacillus strains was performed using CMC as a substrate for determination of the optimal temperature, pH and metal ion supplementation that would yield the highest cellulase activity. From temperatures ranging between 30-90 °C, it was found that 50 °C yielded the highest cellulase activity (Figure 1A). The pH at which the highest cellulase activity was observed at pH 7 for all used strains; although fluctuations in activity between the 4 strains could be noticed at certain pH values (ex. pH 5.5, 8, and 9.5) (Figure 1B). The supplementation of sodium and potassium ions in the medium showed between 2-33% increases in cellulase activity for all 4 Bacillus strains (Figure 1C). Cellulase activities of 181, 215, 172, and 172 U/ml were achieved from MI-1, MI-10, MI-24 and MI-42, respectively, under sodium and potassium supplementation using CMC as substrate. The rest of the tested ions, however, resulted in a reduction in cellulase activity from all 4 strains, with copper and zinc showed the most reduction of activity (71-88%).