Cellulose degradation and ethanol production of different Clostridium strain
热纤维梭菌不同菌株的纤维素降解和酒精生产能力

Cellulose degradation and ethanol production of two types of cellulosic materials with different concentration were evaluated in batch system of mono-cultures of cellulolytic ethanol producing strains (Clostridium thermocellumstrain LQRI and Clostridium thermocellumstrain VPI), and co-cultures of LQRI or VPI in combination with one of the non-cellulolytic ethanol producing strains (Thermoanaerobacter ethanolicus strains X514 or Thermoanaerobacter ethanolicus39E). Results demonstrated that higher cellulose degradation abilities about 1.2 times were detected in LQRI mono-culture than in VPI mono-culture, while no significant difference of ethanol yields was found between the two mono-cultures. Abilities of cellulose degradation and ethanol production decreased significantly with the increasing of substrate cellulose concentration (1%, 2%, 5%). In the co-culture system, cellulose degradation abilities of LQRI were also significantly higher than VPI, the former is 1.28-1.58 times of the latter. Cellulose degradation rate of LQRI + Thermoanaerobacterand VPI+ Thermoanaerobacterdecreased gradually with the increasing of substrate cellulose concentration, while the absolute value of cellulose degradation was also affected by the partner Thermoanaerobacter strain. Additionally, the ethanol yields in the co-cultures of LQRI+Thermoanaerobacterwere significantly higher than that in the co-cultures of VPI+Thermoanaerobacter with same Thermoanaerobacterpartner, the former is 1.27-1.77 times of the latter. However, ethanol yields in the co-cultures have not significantly declined with the increasing of substrate cellulose concentration.