Evaluation of ligninolytic and cellulolytic fungi for degradation of lignocellulosic wastes
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Date
2017
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CCSHAU
Abstract
Fungi play an important role in the biodegradation of lignocellulosic substrates. Therefore, the uses of
lignocellulolytic fungi for biotechnological applications are quite promising. In present investigation, 43 mutually
distinct fungi were isolated from different samples and screened for their ligninolytic and cellulolytic activities.
Physical conditions for nine promising isolates SMT1, SMT2, SMT22, SMT29, HST9, HST11, HST14, HST15
and HST16 were optimized for production of lignocellulose degrading enzymes; laccase, lignin peroxidase,
manganese peroxidase, carboxy methyl cellulase and filter paper degrading activities.All the isolates showed
maximum enzyme activities at 30OC temperature, pH 6, on 6th day of incubation and under stationary
conditions.Maximum cellulolytic activities were shown bySMT2followed by SMT1 and maximum ligninolytic
activities were shown by SMT22 followed by SMT29. Laccase, LiP and MnP activities decreased after addition of
metal ions; however, cellulase activities remained unaffected in the presence of metal ions at optimum
concentration.Among different cellulose substrates, carboxymethyl cellulose (200 mg/L) concentration was
optimized which gave maximum FPase and CMCase activities in case of isolate SMT2. The isolate SMT29 gave
maximum laccase activity and SMT22 showed maximum lignin peroxidase and manganese peroxidase activities at
100 mg/L concentration of alkali lignin.The addition of different ammonium salts at (0.5g/L) showed highest
FPase activity in SMT1 in case of ammonium sulfate whereas highest CMCase activity by SMT2 was observed for
ammonium chloride. Maximum laccase activity was given by SMT22 in case of ammonium chloride whereas
maximum lignin peroxidase activity was given by SMT29 after addition of ammonium sulfate.In case of corn cob,
maximum loss in TOM was observed for SMT22 (65.57%)followed by SMT29 (64.67%); however, in case of
sugarcane bagasse, maximum loss in TOM was observed for SMT29 (33.75%) followed by SMT22 (33.68%).
Initial cellulose, hemicellulose and lignin concentration in corn cob were 35, 42 and 14% respectively, which
reduced to 17, 31 and 9% respectively, in case of SMT2 and 18, 21 and 1% respectively, in case of SMT22 after
30 days of incubation. Likewise, initial concentration of cellulose, hemicellulose and lignin were 41, 25 and 20%
in sugarcane bagasse respectively, which reduced to 31, 15 and 4% respectively, in case of SMT22 and 28, 17 and
13% respectively, in case of SMT2 after 30 days of incubation.On the basis of microscopic characteristics, 7
fungal isolates were identified to be ascomycetes and 2 were basidiomycetes and on the basis of molecular
characterization, SMT2 was identified to be Alternariatenuissima, SMT22 was identified as Aspergillusterreus
strain FJAT-31011 and HST9 was identified as Aspergillusdentatus (Emericella dentate).
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