BIOTECHNOLOGY LETTERS Volume 15 No.3 (March 1993) pp.239-244 received lOth February INFLUENCE OF MEDIA COMPOSITION ON I~ACTIC ACID PRODUCTION RATE FROM WHEY BY Lactobaciilus helveticus A. AMRANE and Y. PRIGENT ~' Universit6 de Rennes I Laboratoire des proc~d6s de separation I.U.T., D6partement Chimie B.P. t 144. 35014 Rennes cedex. France SUMMARY The effect of preculture and culture media formulation on Lactohacillus helveticmv lactic acid production rate was investigated in batch fermentations. Maximum lactic acid productivity of 5.5 g/l.h, was obtained from hydrolyzed whey. Clarified whey ultrafiltrate gave 4.4 g/l.h, at less expense. INTRODUCTION Lactic acid bacteria are known as very fastidious concerning their nutritional requirements (Desmazeaud, 1983), and especially their nitrogen supplementation : according to Vahvaselkh and Linko (1987), Aeschlimann and von Stockar 11990). a culture medium giving rise to fast growth and lactic acid production rates has to be supplemented with yeast extract ; as shown by Francou t1986), Baralle and Borzani (1988), lactic yeast autolyzate may be used instead of veast extract : Leh t 1987) also reported that whey proteins enzymatic hydrolyzates may be regarded as a fair nitrogen source. In contrast to this, little attention has been paid to inoculum preparation ( Reddy et al., 1976 ; Roy et al., 1986 ; Vahvaselk~i and Linko, 1987) : usually, lactic acid bacteria are precultivated on skim mill The main purpose of this paper is to investigate how media composition /nitrogen sources, total phosphorus concentration) influences lactic acid production rate. MATERIAI,S AND METItOI)S The Lactobacilht~ helveticus strain milano used throughout this work was kindly supplied by EVEN (Ploudaniel, France). Seed culture and culture media were prepared from the tollowing carbon sources : fresh sweet cheese whey (FW), reconstituted sweet cheese whey powder ~WPL or their hydrolyzates (suffix H) by a protease of Bacillus subtilis (B500. GIST-BROCADES, S6clin. France) according to Leh (1987). For some experiments, whey was clarified 239