METABOLIC RESPONSE OF BACILLUS-SPHAERICUS 1593M FOR DUAL-SUBSTRATE LIMITATION IN CONTINUOUS AND TOTAL-CELL-RETENTION CULTURES

A chemically defined medium has been developed to support the growth a nd the production of mosquito larvicidal factor(s) (MLF) of Bacillus s phaericus 1593M. On the basis of the data of steady-state continuous c ultures, it has been understood that acetate can serve as a sole carbo n and energy source for B. sphaericus 1593M. Utilization of acetate by B. sphaericus 1593M and the production of MLF are further enhanced by the addition of glutamate at low concentrations, both in steady-state continuous as well as in total-cell-retention cultures (TCRC). A two- step TCRC procedure resulted in better biomass and MLF production by B . sphaericus 1593M. It was also found that glutamate can serve as a ca rbon source as well as a growth factor in the presence of acetate and hence is a partially substitutable carbon source.