Isolation of Cellulose Degrading Bacteria from Rumen and Evaluation of Cellulase Production by the Isolate Using Lignocellulosic Substrate

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Abstract

The utilization of cheaper substrates reduces cost of cellulase production and there is the need for cellulolytic microbes capable of degrading lignocellulosic materials. Therefore, this study was aimed to isolate and identify bacteria from rumen fluid, and evaluate wheat straw, sorghum straw and bagasse for cellulase production. Rumen fluid were collected from cattle, goat and sheep slaughtered at Haramaya town abattoir. Wheat and sorghum straw, and bagasse were obtained from Haramaya University research plot and Wonji-Shewa Sugar Factory, respectively. One-way analysis of variance (ANOVA) was used for data analysis using SPSS version 20. Microscopic and Biochemical tests of potential cellulase producers were carried on Luria Bertoni Agar enriched with 1% Carboxymethyl cellulose of sodium (CMC-Na). Cellulase production was evaluated using submerged fermentation. The potential CMC degrading isolate (HUG-3b) and (HUS-2a) from goat and sheep rumen fluids, respectively, were identified as Pseudomonas sp. and isolate (HUC-4b) from cattle rumen fluid was identified as Aeromonas sp. Pseudomonas sp from goat rumen produced significantly the highest carboxymethyl-cellulase (CMCase) and filter-paperase (FPase) of 1.54 ± 0.10 U/ml, 1.46 ± 0.09 U/ml from fermentation of 1% w/v Carboxymethyl cellulose used as standard and 1% wheat straw, respectively (p < 0.05), whereas, Pseudomonas sp. from sheep rumen produced significantly the highest CMCase of 1.81 ± 0.27 U/ml from fermentation of 1% wheat straw(p < 0.05) and insignificantly highest FPase of 1.27 ± 0.22 U/ml from fermentation of 1% bagasse(p > 0.05). Aeromonas sp. produced insignificantly the highest CMCase and FPase of 2.31 ± 0.17 U/ml, 1.50 ± 0.02 U/ml from fermentation of 1% and 2% wheat straw, respectively (p > 0.05). It can be concluded that the fermentation of 1% and 2% wheat straw by Aeromonas can be utilized for the maximum production of cellulase.  Identification of the species or strain of isolate using molecular technique will be recommended.