“…As a rule, many fungal laccases exhibit pH optima in the acidic pH range that vary depending on the type of substrate: for ABTS from pH 2–5, for 2, 6-dimethoxyphenol in the range of pH 3–8 and for syringaldazine between pH 3.5 and 7.0 (Baldrian 2006). Muhammad et al (2012) have reported the maximum laccase activity at pH 5.0. Chaurasia et al (2013a, b) have reported the maximum laccase activity at pH 5.0.Fig.…”
Section: Resultsmentioning
confidence: 96%
“…Shujing et al (2013) have reported optimum temperature at 50 °C. Muhammad et al (2012) have reported the maximum laccase activity at 40 °C. Guo-Qing et al (2010) have showed that the maximum activity of laccase was observed at 60 °C.…”
A novel laccase-producing white-rot fungus, Marasmius sp. BBKAV79 (Genbank Accession Number-KP455496, KP455497), was isolated and subjected to purification, characterization and dye decolorization study. The purified enzyme was obtained with a specific activity of 0.226 U mg -1 protein and a final yield of 13.5 %. The enzyme was found to be a monomeric protein with a molecular mass of *75 kDa as estimated by non-denaturing polyacrylamide gel electrophoresis (PAGE) and further confirmed with zymogram analysis. The optimal pH and temperature of the laccase was recorded to be 5.5 and 40°C, respectively. The metal ions Hg 2? and Ag ? were found to drastically inhibit the activity of laccase at the rate of 96.6 and 96.5 %, respectively. Nevertheless, Fe 3? was found to inhibit laccase activity at 40 %. Phenylmethanesulfonyl fluoride (PMSF) strongly inhibited the laccase activity, and additives viz, sodium dodecyl sulfate (SDS), hydrogen peroxide (H 2 O 2 ) and sodium chloride (NaCl) were known to follow the earlier pattern of enzyme inhibition. The values of kinetic parameters K m and V max for purified laccase were noted at 3.03 mM and 5 lmol min -1 , respectively, for guaiacol as substrate. The textile dyes were decolorized at a range of 72-76 % and 88-93 % when treated with Marasmius sp. BBKAV79 and purified laccase, respectively. Based on the outcome of the present investigation, it could be, therefore, inferred that laccase isolated from Marasmius sp. BBKAV79 effectively decolorizes the textile dyes; however, the metal ions Hg 2? , Ag ? and Fe 3? and agents like PMSF, SDS, H 2 O 2 and NaCl pose an effective inhibitory potential under specified physicochemical conditions.
“…As a rule, many fungal laccases exhibit pH optima in the acidic pH range that vary depending on the type of substrate: for ABTS from pH 2–5, for 2, 6-dimethoxyphenol in the range of pH 3–8 and for syringaldazine between pH 3.5 and 7.0 (Baldrian 2006). Muhammad et al (2012) have reported the maximum laccase activity at pH 5.0. Chaurasia et al (2013a, b) have reported the maximum laccase activity at pH 5.0.Fig.…”
Section: Resultsmentioning
confidence: 96%
“…Shujing et al (2013) have reported optimum temperature at 50 °C. Muhammad et al (2012) have reported the maximum laccase activity at 40 °C. Guo-Qing et al (2010) have showed that the maximum activity of laccase was observed at 60 °C.…”
A novel laccase-producing white-rot fungus, Marasmius sp. BBKAV79 (Genbank Accession Number-KP455496, KP455497), was isolated and subjected to purification, characterization and dye decolorization study. The purified enzyme was obtained with a specific activity of 0.226 U mg -1 protein and a final yield of 13.5 %. The enzyme was found to be a monomeric protein with a molecular mass of *75 kDa as estimated by non-denaturing polyacrylamide gel electrophoresis (PAGE) and further confirmed with zymogram analysis. The optimal pH and temperature of the laccase was recorded to be 5.5 and 40°C, respectively. The metal ions Hg 2? and Ag ? were found to drastically inhibit the activity of laccase at the rate of 96.6 and 96.5 %, respectively. Nevertheless, Fe 3? was found to inhibit laccase activity at 40 %. Phenylmethanesulfonyl fluoride (PMSF) strongly inhibited the laccase activity, and additives viz, sodium dodecyl sulfate (SDS), hydrogen peroxide (H 2 O 2 ) and sodium chloride (NaCl) were known to follow the earlier pattern of enzyme inhibition. The values of kinetic parameters K m and V max for purified laccase were noted at 3.03 mM and 5 lmol min -1 , respectively, for guaiacol as substrate. The textile dyes were decolorized at a range of 72-76 % and 88-93 % when treated with Marasmius sp. BBKAV79 and purified laccase, respectively. Based on the outcome of the present investigation, it could be, therefore, inferred that laccase isolated from Marasmius sp. BBKAV79 effectively decolorizes the textile dyes; however, the metal ions Hg 2? , Ag ? and Fe 3? and agents like PMSF, SDS, H 2 O 2 and NaCl pose an effective inhibitory potential under specified physicochemical conditions.
“…The mixture was centrifuged at 10000 rpm for 10 min at 4°C and then mixed with 1.0 mL, 0.05mol L -1 acetate buffer having pH 5.0. All contents centrifuged again and dialyzed against 2L same acetate buffer via method followed by Aslam et al 36 . The dialyzed extract was purified through a DEAE sephadex column using 0.1-1.0 M NaCl by ion exchange chromatography 31 .…”
Section: Partial Purification and Determination Of Molecular Weightmentioning
Laccases are the widely distributed oxidative enzymes belong to the group of phenoloxidases. These are considered as model enzymes and widely distributed in nature. Bacterial laccases have extremophilic nature and several other unique properties that are not features of fungal laccase such as hightemperature stability and pH. The present study focused on the optimization of laccase production from Bacillus sp. AKRC01 under submerged fermentation state using agro-waste as the substrate. The optimized environmental conditions such as incubation period 96 hours, temperature 35°C and pH 8.0 were obtained maximum enzyme production 3.832 U/ml. In addition, optimized the carbon and nitrogen sources such as 2.0% glucose (4.967 U/mL) and 1.0% peptone (6.236 U/mL) resulted in maximum enzyme production with rice bran as an effective agro-waste substrate. Laccase enzyme was partially purified via ammonium sulfate precipitation method and chromatography using the sephadex column and determination of the molecular weight of 61 kDa compared with the protein ladder was done by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The findings of this study demonstrated the ability of Bacillus sp. AKRC01 using low-cost agro-waste for laccase production. Laccases are important enzymes that have several industrial applications such as bioremediation, bio pulping and food industry.
“…Fungi contribute more to the decomposition of recalcitrant matter such as lignin with extracellular laccase enzymes [optimum pH of 3-6 e.g. [71][72][73][74][75]. Soil pH also influences the adherence of OM to mineral surfaces and subsequently its decomposition rate.…”
Soil organic carbon (SOC) has an essential role in controlling ecosystem functions associated with soil physical, chemical and biological properties. Maintaining the SOC pool size in agroecosystems is important to sustain food security, protect soil biodiversity and buffer environmental impacts. The SOC pool is dynamic, with losses occurring due to CO 2 mineralization and gains from microbially mediated humification of organic substrates into stable C compounds. Bioenergy production from lignocellulosic feedstock implies that greater amounts of plant residues will be removed from agroecosystems and could deplete the SOC pool, based on empirical models and experimental results from long-term field trials. In northern temperate regions, several management practices are suggested to conserve the SOC pool, such as the application of biochar, judicious use of organic and inorganic fertilizers, crop rotations that include high biomass producing non-bioenergy crops or intercropping systems that combine perennial bioenergy crops with other crops (annuals or trees). Moreover, new technologies such as genetically modified (GM) bioenergy crops are recommended to enhance bioenergy production per unit energy input. Those modifications include GM crops with higher resource-use efficiency (i.e., for water, nutrients and light), GM crops with cellulase/ligninase enzyme systems for biofuel production and GM crops with higher calorific values that release more energy during combustion.
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