Methanol has attracted much attention due to many advantages as a raw material in the fermentation process. The methylotrophic bacterium Methylobacterium oraganophilum produces a high viscosity polysaccharide , Methylan, from methanol as a sole carbon and energy source. The methylan fermentation, by M. oraganophilum was conducted in a fed-batch fermentation to obtain a high methylan productivity. An accurate control of methanol was required in the fed-batch fermentation. But it was difficult to maintain methanol concentration in the broth with the feeding technique based on DO-stat and the fluctuation of methanol concentration during the culture was observed.
In this study we have used an alcohol sensor to measure and control the Methanol concentration in fed-batch fermentation. The response time of the alcohol sensor was about 12.5 sec and a linear relationship was observed between the sensor signal and the methanol concentration fo the medium below 4g/L. The sensitivity and selectivity of the alcohol sensor for the measurement of methanol concentration was found to be satisfactory. Using this alcohol sensor, the methanol concentration could be measured and controlled on-line during the fed-batch fermentation. The final concentration of cell and
methylan in the fed-batch culture using alcohol sensor were 25g/l and 17.5g/l. Methylan production were enhanced by 40% compared with methylan production obtained in DO-stat method.
