Study of the effects of temperature and pH on lactic acid production from fresh cassava roots in tofu liquid waste by Streptococcus bovis

摘要

We report a study of the effects of temperature and pH on the kinetics of lactic acid production from fresh cassava roots(FCR)by Streptococcus bovis in new media:tofu liquid waste(TLW);TLW with 2 wt% concentrated maguro waste(TLW+CMW2);and in a standard trypto-soya broth(TSB)compared with a standard medium(glucose in TSB).The results showed that 39 deg C and pH 5.5 were optimal for fermentation properties(lactic acid concentration,productivity and specific growth rate)in all media,including the standard.The energy of activation(E_a)and the energy of deactivation(E_d)of lactic acid fermentation in all media were calculated using the Arrhenius relation.The E_a and E_d values increased in the order FCR in TLW