Screening And Characterization Of Anaerobic Cellulolytic Microorganisms

Nowadays, people were confronted with many problems which were in direneed of solutions, such as energy sources crisis, the lack of food supplies, and thedeteriorating environment. And production of ethanol from cellulose was aprospective method. Our country, an agriculture Great Power, produced a greatdeal of cellulosic materials. Because these cellulosic materials were usedimproperly, such as most of them were fired, it not only wasted resource but alsoworsened the environment. In anaerobic ecosystem, there existed plenty ofmicroorganisms which could degrade cellulosic materials. If we can screen outmicroorganisms or complexes with high cellulolytic activity, we could reduce thecost of ethanol production, and accelerate the industrialization. These would beimportant for the proper use of resource, increasing energy sources and reducingthe pollution.In our research, we separated 7 floras in the initial screening, and we studiedtheir ability of cellulase production. We screened out two complexes, 2# and 3#,from mixed rumen microorganisms with the ability to ferment cellulose. In thispaper, the complexes'abilities of cellulosis were evaluated and analyzed.By the method of dry matter loss (DML %), it exhibited that when1.0g/100mL filter paper was the sole carbon and energy source, 2# complex'saverage dry matter loss was 38.70%, and the best value was 45.40%. From theresult of 2# complex's cellulase activity by the method of DNS, it was showedthat CMC activity gradually increased in the initial stages of the incubation.After 72 hours, CMC activity reached around 120U, and the maximum CMCactivity was 129.4U. Differently, 2# complex's filter paper activity (FPA) couldreach 94.6U in a short time. After the FPA reached 103.6U, it kept on around100U. We inoculated different volume rate of microorganisms'inoculationranging from 14.3% to 100% into the media. Then we measured theconcentration of glucose of 2# complex's incubation and the activity of itscellulase. The maximum concentration of glucose almost was an order ofmagnitude higher than the normal incubation. The CMC activity had similarvalue, 150U or so. When the volume rate of inoculation was 50%, there was the minimum, 85.5U. Relatively, the FPA was fluctuant, and when the volume rateof inoculation was 100%, the value was, 238.3U. The maximum was almosttwofold of the minimum which was 118.2U.With the same methods, we measured the 3# complex's dry matter loss andcellulase activity. When the filter paper as the sole substrate, the dry matter losswas the maximum, which reached 34.2%, and when the treated straw as the solesubstrate, the dry matter loss was lowest, which reached 12.4%. At the 24th hour,3# complex's cellulase activity represented higher than 80U, and it increasedupwards of 100U after 48 hours. Then, 3# complex's cellulase activity remainedits high activity. The cellulase activity's maximum was 109.4U, appeared at the72nd hour. The concentration of glucose in 3# complex's incubation increased asthe volume rate of inoculation increased. And the cellulase activity also changedevidently. When the volume rate of inoculation was 50%, it showed the minimumof 3# complex's cellulase activity, reached 141.2U. Even when the volume rateof inoculation was only 33.3%, the cellulase activity was next to the highestvalue, approximately reached 121.6U. In other situation with different volumerate of inoculation, they exhibited lower cellulase activity, however, also reachedaround 80U.