Assessing the cellulase enzyme heterogeneity of bacterial strains and their feedback to cattle manure degradation in a greenhouse model of in vivo pond ecosystem.

The responses of cellulase enzymes of three bacterial isolates and their impacts on cattle manure decomposition were assessed in a greenhouse model in vivo pond ecosystem. Fifty grams of fresh cattle manure was placed in a fastened nylon bag (mesh size ~ 50 μm dia.) and placed in triplicate in a plastic bucket with 10 l of pond water which was hung inside the enclosed polyhouse, semi-closed and open systems for 4 weeks. Samples of manure residue directly from nylon bag and water from manure leached bucket water, water, and soil from the enclosed polyhouse were collected for enzymatic assays, enumeration of aerobic cellulose decomposing and heterotrophic bacteria, and determination of water and soil quality parameters. Responses of cellulases to different temperatures in situ were also elucidated. The values of test bacteria, endoglucanase, exoglucanase and β-glucosidase, and organic carbon were significantly (P ˂ 0.05) higher in the closed system compared to semi-closed or open system. Priming of all the enzymes coupled with the peak of aerobic cellulose decomposing bacteria and heterotrophic bacterial populations occurred on the day 14 or 21 in vivo. Since the peaks of three cellulases of bacterial isolates (KUPH1, KUPH6, and KUPH8) were demonstrated between 35 and 40 °C, and that temperature coincided with temperature of the greenhouse model, this temperature range appeared to favor the growth of cellulose decomposing bacterial populations and involved cellulase enzymes.