Abstract
Arthrobacter oxydans (PG21-1) which was isolated from soil preferably assimilated 1, 2-propanediol and produced remarkable amount of lactic acid. Cultural conditions for lactic acid production from 1, 2-propanediol were studied using a 15 liter jar fermentor. Optimum pH and urea concentration for the production of lactic acid were 8.0 and 0.3%, respectively. Under these conditions, the yield of lactic acid was 17.8g/liter in 7 day cultivation. About 70% of the utilized 1, 2-propanediol was converted to lactic acid. The production of lactic acid by resting cells was also investigated. Resting cells of Arthrobacter oxydans showed a high activity to produce lactic acid at alkaline pH and the amount of the acid reached to 10.2g/liter in 12 hr incubation. The accumulation of lactic acid at alkaline side was considered to due to the strong suppression of the degradation of lactic acid.
