Assessment and development of microbial biofilms for efficient degradation of paddy straw
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Date
2020
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Punjab Agricultural University, Ludhiana
Abstract
An experiment was conducted to assess the potential of lignocellulolytic microorganisms and
their biofilms for paddy straw degradation. Fifty four fungal and 10 bacterial cultures were
screened qualitatively on the basis of zone formation for cellulolytic (31 cultures,0.2-5.1cm),
hemi-cellulolytic (13 cultures,0.3-1.8cm) and lignolytic activities (15 cultures,0.2-1.8cm).
Quantitatively, during submerged and solid state fermentation, highest cellulase and laccase
activities were obtained by culture17 (0.709IC/ml and 0.666IU/ml), and Lignin7
(0.821CU/ml and 3.919CU/ml), whereas, highest xylanase activity was observed in culture
F2C5 (0.840IU/ml) and L1C8 (1.555IU/ml), respectively. On the basis of functional properties
and growth characteristics, 11 lignolytic, 10 cellulolytic and 9 xylanolytic cultures were used
for interaction studies. After testing for compatibility, cellulolytic (Culture17&Compost
fungus), xylanolytic (F2C5&L1C8) and lignolytic fungi (Lignin7&White4) were selected for
biofilm formation. Under laboratory conditions, the biofilms were used for paddy straw
degradation and treatment T14(Bacillus subtilis+CF1+CF2+XF1+XF2+LF1+LF2) showed
best results after 30&60 days for reducing cellulose (28.9&24.1%), hemicellulose
(16.6&13.4%) and lignin (6.8&5.8%) content of paddy straw. The effect of sequential
addition of cellulolytic, hemi-cellulolytic and lignolytic cultures on paddy straw degradation
was tested for 21 days in which treatment B14 resulted in highest decrease in cellulose
(32.8%), hemicellulose (24.3%) and lignin (7.3%). The best biofilm was further evaluated
using different N and C sources and treatment T7 supplemented with ammonium
sulphate@0.5% and jaggery@1% was found to be most effective in degrading the paddy
straw. A significant reduction was observed in cellulose (26.0%), hemicellulose (31.2%) and
lignin (44.4%) content as compared to 9.4%, 6.8% and 22.6% in control, respectively.
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Citation
Gurshinderdeep Singh (2020). Assessment and development of microbial biofilms for efficient degradation of paddy straw (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.