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CHARACTERIZATION, PRODUCTION OPTIMIZATION AND APPLICATION STUDIES OF LACCASE FROM SOIL FUNGI USING SAWDUST AS SUBSTRATE

AKINYEMI, OLUWATOBI DOMINION (2021) CHARACTERIZATION, PRODUCTION OPTIMIZATION AND APPLICATION STUDIES OF LACCASE FROM SOIL FUNGI USING SAWDUST AS SUBSTRATE. Masters thesis, Covenant University Ota..

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Abstract

Challenges of low yield and high production costs remain the major obstacles to laccase production and application. In this study, fungi were isolated from sawdust-polluted soils collected from Morogbo-Agbara, Iju and Ota in Ogun State, Nigeria. The fungal isolates were identified as Aspergillus niger, Penicillum sp, Aspergillus flavus, Penicillium expansum, Rhizopus sp, Saccharomyces cereviseae, Fusarium sp, Cryptococcus sp and Candida sp This was done after the physicochemical assessment of the soil and sawdust samples. The isolates were screened for laccase production ability using tannic acid; and specific DNA primers (laccase degenerate and laccase-1) to identify laccase genes in the isolates before sequencing. Five of the ten fungal isolates were positive for laccase screening using tannic acid. Using sawdust as a substrate under solid-state fermentation (SSF) conditions, significant medium components were selected via the Plackett-Burman design. Thereafter, the Central Composite Design (CCD) of response surface methodology (RSM) was used to optimize the significant variables – Glucose, (NH4)2SO4. Sample ML2 showed highest laccase activity of 1.984 U/ml after 14 days, followed by ML5 (1.807 U/ml) and IL2 (1.241 U/ml). Laccase yield was observed to be strongly impacted by glucose, ammonium sulphate ((NH4)2SO4), and the liquid/solid (L/S) ratio in ML2. The yield was raised by two folds (3.975 U/ml) after optimization. The result of the degradation potential of the produced laccase on spent engine oil showed effective degradation of 78 % and a minimum of 51 %. The findings of this study show sawdust as a useful waste substrate in the optimized production of fungal laccases.

Item Type: Thesis (Masters)
Uncontrolled Keywords: laccase, soil, sawdust, fungi, fermentation,
Subjects: Q Science > QR Microbiology
Divisions: Faculty of Medicine, Health and Life Sciences > School of Biological Sciences
Depositing User: Mrs Patricia Nwokealisi
Date Deposited: 14 Oct 2021 11:32
Last Modified: 14 Oct 2021 11:32
URI: http://eprints.covenantuniversity.edu.ng/id/eprint/15377

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