Physiological restriction of the <i>L</i>‐lactic acid production by <i>Rhizopus arrhizus</i>

Abstract

Abstract The influence of basic physiological factors on the quality of inocula and L (+)‐lactic acid production by Rhizopus arrhizus CCM 81 09 were studied. The most effective preparation of the spores (5 × 10 7 spores/ml) and subsequent good lactate production was achieved on the agar medium with soil extract and malt agar. The optimum initial amount of active spores for inoculation was 10 3 –10 4 spores/ml. The preparation of inoculum required intensive stirring with lower aeration and pH maintained in the range from 4.8 to 6.0 by the addition of CaCO 3 . The maximum yield of lactic acid production was achieved by using 5% (v/v) of 24‐h‐old inoculum. The intensity of lactic acid production in the inoculum was proportional to its production in the subsequent steps of fermentation and can be used as a fast control of the physiological state of the producers.