Physiological restriction of the L-lactic acid production by Rhizopus arrhizus

The influence of basic physiological factors on the quality of inocula and L(+)-lactic acid production by Rhizopus arrhizus CCM 8109 were studied. The most effective preparation of the spores (5x10(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 CaCO3. 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.