Effects of alcohols on bacterial cellulose production by Acetobacter xylinum 186

To improve the yield of cellulose production in bacteria, we investigated the stimulatory effects of six different alcohols during fermentation of Acetobacter xylinum 186. Our study showed that after static fermentation at 30A degrees C for 6 days, bacterial culture with 1.0% (v/v) of methanol added in the medium produced the highest bacterial cellulose (BC) yield at 103.5 mg/100 ml, which was 21.8% higher than the control group. Addition of 0.5% of ethylene glycol in the culture yielded 105.5 mg/100 ml BC, 24.1% higher than the control group. Adding 0.5% of n-propanol yielded 96.4 mg/100 ml BC, 13.4% higher; 3.0% of glycerol yielded 108.3 mg/100 ml BC, 27.4% higher; 0.5% of n-butanol yielded 132.6 mg/100 ml BC, 56.0% higher; and 4.0% of mannitol in the culture yielded 125.2 mg/100 ml BC, 47.3% higher, respectively. The rate of bacterial cellulose production increased with the growth rate of the bacteria. The stimulatory effects of these alcohols that we observed were significant in the later stage of fermentation, which was considered to be important for the biosynthesis of bacterial cellulose.