NeemishaGurpreet Singh2017-10-102017-10-102017http://krishikosh.egranth.ac.in/handle/1/5810032744An experiment was conducted to assess the potential of cellulolytic microorganisms for paddy straw degradation. Twenty seven samples representing hot spots for cellulolytic microorganism were collected from eight different locations. A total of 653 microorganisms were isolated including bacteria (520), fungi (100) and actinomycetes (33). The cultures were screened for cellulolytic activity using both qualitative as well as quantitative assay. Among all the cultures tested, only 48 cultures (44 bacteria, 2 actinomycetes and 2 fungi) exhibited cellulase activity. The zone of hydrolysis varied from 0.3 to 3.2cm and largest zone of hydrolysis was obtained by CDM35 (3.2cm). Hemicellulase activity was exhibited by 24 cultures and largest zone of hydrolysis was produced by CDM 23 (2cm). Quantitative estimation of cellulase enzyme was done using DNS method in which highest cellulase activity of 0.29 IU/ml was shown by CDM 26 followed by 0.19 IU/ml by CDM35. All the cultures were characterized using cultural, morphological and biochemical characterization techniques. The genetic diversity of most efficient bacterial isolates was determined using BOX-PCR, ERIC-PCR and 16S rDNA amplification. The dendrogram obtained from pooled data of BOX and ERIC fingerprints resulted in the formation of two major groups at 15% similarity, subgroups at 23% similarity and the maximum similarity obtained was 57%. Functional characterization revealed IAA production by all the isolates however, only 8 cultures exhibited P solubilization capability. Majority of the microorganisms exhibited optimum growth at 30-45˚C. On the basis of all the qualitative assays, quantitative assays, optimum growth temperature and pH, most efficient microorganisms were selected for assessment of degradation potential under glasshouse and field conditions. Ten most efficient cultures consisting of seven bacteria (CDM5, CDM4, CDM7, CDM3, CDM35, CDM2, CDM23), two actinomycetes strains (CDM26 and CDM42) and one fungal strain (CDM45) were selected for experiment. Under glass house conditions treatments T13, T14. T17 & T20, and under field conditions, treatments T5, T6 & T9 performed efficiently in decreasing ADF and NDF.enThesis