Isolation Of Butanol Produtcion Strain And Construction Of Co-Culture System With Cellulose

Bio-energy is a renewable energy resource, which can effectively solve the problem of energy crisis, environmental pollution and ensure enconomic sustainable development. Butanol as a new generation of biofuel, has a number of prominent advangtages over ethanol, such as higher energy density, lower hygroscopicity, lower corrovisity and it can blend with gasonline in any ratio, therefore, the world pays more and more attention on how to develop butanol produtcion. With the development of Consolidated bioprocessing(CBP), researchers are more interested in using cellulose biomass which is abundant in the environment to obatin butanol. However, due to the complexity of cellulose structure, current strains for butanol production are incapable of converting celluose into butanol directly, in this circumstance, designing a co-culture system which combining cellulose-degrading strain and strain for butanol product is gaining more attention.In this study, we dedicated to screen serveral mesophlic and anaerobic strains which have certain ability to produce butanol by enrichment and domestication culturing, subsequently co-cultured with cellulose degrading consortium N3 to use celluose as a sole carbon resoruce to produce butanol. We isolated 6 strains which can producing butanol from soil sapmels and the strain F6 is superior to the other strains. After 96 h of fermentaion by the strain F6, butanol concentration was 5.21 g/L, acetone concentration was 2.52 g/L and ethonal concentration was 1.01 g/L. The strain F6 belonged to gram positive microbes, and it could produce spore, futher charcteriziation of strain F6 by sequence alignment of 16 S r RNA showed that strain F6 share 99% similarity with Clostridium beijerinckii CP23-KKU in max ident. Concerned with morphological character and physiological biochemial character of strain F6, we confirmed that strain F6 belongs to C. beijerinckii.Based on the machanism of synergistic effect between microorganisms, we bulit two co-culture systems, celluose degrading consortium N3 which was preserved in laboratory with C. beijerinckii F6 and celluose degrading consortium N3 with C. beijerinckii 709 which was also preserved in laboratory. The result showed that F6 co-culture system has relatively higher butanol production than 709 co-culture system. With respect to Effect of butanol production strains culture period on butanol production, we found that when we inoculate strain F6 into medium after 48 h cultivation of consortium N3, the system showed highest buntaonl yield, however, it was 96 h in 709 co-culture system. The two co-culture systems also had many similarities, when the initial p H of medium was 7, the initial concentration of filter paper cellulose was 20 g/L and all the strains cell density increased to 2 m L OD600 of 1.0, both of the system is more sufficient to produce butanol. In C. beijerinckii F6 co-culture system,the best butanol concentration is 0.291 g/L, and in C. beijerinckii co-culture system is 0.215 g/L. With the construction of co-culture system, it showed the ability to use butanol production strain to convert cellulose into butanol directly, the results can provide theoretical basis for use cellulose to produce butanol.