USING BY MUTANT STRAINS C. ACETOBUTYLICUM LIGNO-CELLULOSIC MATERIAL AS A SUBSTRATE

Aim. To create a mutant strain with increased accumulation of butanol by chemical mutagenesis (mutating agent N-methyl-N-nitro-N-nitrosoguanidine) cultured on switchgrass biomass mash. Methods. To obtain the mutant strain there were used the method of induced mutagenesis. To determine the production of alcohols there were used gas chromatography. Results. Processing C. acetobutylicum ІMB culture B-7407 (IFBG C6H) via the mutagen N-methyl-N-nitro-N-nitrosoguanidine, led to 99% cell death. There were obtained a mutant resistant strain C. acetobutylicum IFBG C6H 5M which produced 45% more butanol on lignocellulosic materials (switchgrass biomass Panicum virgatum L) compared with the parent strain. It has been shown that the strain does not change its feature to increased synthesis of butanol over 10 passages. The strain of C. acetobutylicum IFBG C6H 5M had a similar morphology to the original strain, but gained the ability to use askulin and trehalose as a substrate. The optimal parameters of the pretreatment of raw materials (crushing ratio, the concentration in the fermentation medium, the temperature and time of cooking) for the cultivation of a mutant strain have been found. It is shown that the optimal concentration of switchgrass biomass in fermentation medium was 60 g/l. It has been shown that the highest concentration of butanol (2.6 g/l and 1.8 g/l to mutant and original strain) accumulated in the culture liquid using raw material pretreated at 2 atm. for 2 hours. Conclusions. Using the methods of induced mutagenesis promising strains can be obtained, which together with optimizations cultivation parameters have an increased yield of the desired product as compared to the parent strain.