ICAR Research Data Repository for Knowledge Management
Bacterial delignification of paddy straw
KrishiKosh
View Archive Info| Field | Value | |
| Title |
Bacterial delignification of paddy straw
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| Creator |
Anita
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| Contributor |
Malik, Kamla
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| Subject |
Aromatic compounds, Enzymes, Bacteria, Crop residues, Rice, Cellulose, Fungi, Polysaccharides, Selection, Inorganic compounds
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| Description |
India is the second largest producer of paddy in the world after China and produces 98 million ton of paddy with roughly 130 million ton of straw. Field burning is the major practice for removing paddy straw which results in nutrient losses, increases the air pollution and consequently affects public health. Lignin is one of the most abundant aromatic natural substances present in the biosphere. It is a polymer composed of phenylpropanoid units, associated with cellulose and hemicelluloses in plant cell. In biological treatment systems, a wide variety of microorganisms including fungi, actinomycetes and bacteria have been used in lignin biodegradation. Now a day, the ligninolytic bacteria gaining importance, because of wider tolerance of temperature, pH and oxygen limitation than fungi. In the present study, a total of 30 bacterial isolates were obtained from soil and different ecological niches. Out of these, 15 isolates were screened for ligninolytic activity on LB media containing dyes (aniline blue, phenol red and guaiacol).The zone index varied from 2.7 to 3.7 with bacterial isolate DS2 showing the maximum zone of clearance (3.7) on LB media containing aniline dye. Only eight bacterial isolates were selected for measuring the ligninolytic enzyme activity in MSM broth containing 1.0% lignin. The activity of laccase varied from 2.34 – 3.56 U/ml, manganese peroxidase (MnP) ranged from 1.48- 4.12 U/ml and lignin peroxidase (LiP) varied from 2.37- 5.99 U/ml. The bacterial isolate, LS1 had both the highest laccase (3.56 U/ml) as well as lignin peroxidase (5.99 U/ml) activity. However, maximum manganese peroxidase activity was observed in PS1 (4.12 U/ml). All bacterial isolates (except PS1) produced maximum lignin peroxidase enzymes activity as compared to other enzyme. Five selected ligninolytic bacterial isolates were used for the delignification of paddy straw with different conditions like temperatures (25, 30 and 35°C), pH (5.0, 6.0 and 7.0) and incubation period (7, 14 and 21 days) under stationary condition. Optimum temperature for delignification was found to be 30°C and pH 6.0 for DS2 and LS1 whereas pH 7.0 for CS3, CS4 and PS1) after 21 days of incubation. The maximum lignin reduction (32%) was observed by isolate DS2 followed by LS1 (30%), therefore, DS2 and LS1 were scored as best isolates for delignification of paddy straw. |
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| Date |
2016-10-22T14:15:19Z
2016-10-22T14:15:19Z 2015 |
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| Type |
Thesis
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| Identifier |
http://krishikosh.egranth.ac.in/handle/1/81406
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| Language |
en
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| Format |
application/pdf
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| Publisher |
CCSHAU
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