Effect of straw apoplast protein on cellulase activity / 生物工程学报

We studied the alteration of the maize straw apoplast proteins in the process of preservation, and analyzed the effects of apoplast proteins on Penicillum expansum cellulase activities. The results show that: the extractable apoplast proteins are gradually decreased during the preservation of maize straw. Meanwhile, their synergistic effects on P. expensum cellulose are also attenuated. The apoplast proteins extracted from fresh maize straw possess endogenous EG activities, which is unstable and completely vanished after 6 months preservation. The apoplast proteins from the preserved straw exhibit significant synergistic effect on FPA, cotton lyase and beta-glucosidase. The maximal synergistic values are 95.32%, 102.06% and 96.6%, respectively. But interestingly, they inhibit the CMCase activity (max. 49.52%). Apoplast proteins show distinctive synergy with betaG and EG, but have no effect on CBH activity. After eliminating the effect of endogenous EG, the apoplast proteins from fresh maize straw have enhanced synergistic or inhibiting effects on FPA, Cotton lyase, betaG and CMCase than those extracted from the preserved straw. Based on our observation, the apoplast proteins play important roles in regulating the cellulase activities. The detailed analysis of the related mechanisms will greatly benefit the studies of the natural biomaterials hydrolysis.

The periodic change of environment factors in solid state fermentation and effect on microorganism fermentation / 生物工程学报

The periodic change of environment factors in air pressure oscillation solid state fermentation bioreactor was studied. Based this research the effect of the periodic environment stimulations on Penicillium decumbens JUA10 cultured in solid state substrate was researched too. The research results showed that in this bioreactor air temperature and relative humidity had large amplitude periodic change drived by air pressure oscillation. The changes had same frequency with the air pressure Oscillation and had amplitude that increased with the air pressure increased. When the press lower limit and upper limit were 0.0MPa and 0.2MPa respectively, pulsating period was 20 min, contrast to the period gather breath solid state fermentation, the air press pulsating SSF had a 2.29 times total CO2 production increase, 3.2 times enzyme activity increase and 1.04 times biomass increase. The data suggested air press pulsating stimulation not only increased biomass but also the metabolic activity.