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

Abstract

The influence of basic physiological factors on the quality of inocula and L(+)-lactic acid production by Rhizopus arrhizus CCM 8 1 09 were studied. The most effective preparation of the spores (5 x 107 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 103-104 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 C a C 4 . 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.

Production of lactic acid and fungal biomass by Rhizopus fungi from food processing waste streams

“…The estimation of starch was carried out using the iodine colorimetric method described by Jin et al [19]. Lactic acid and total sugars were measured by HPLC.…”

“…Research on lactic acid production by Rhizopus spp. has continued primarily because of the ease of product separation and purification and the ability of the fungus to utilize both complex carbohydrates and pentose sugars [5,7,19]. Among the Rhizopus fungi, R. oryzae has received the greatest interest and strain R. oryzae NRRL 395 has been recognized as one of the most suitable lactic acid producers [5,8,[20][21][22][23].…”

Direct fermentation of potato starch wastewater to lactic acid by Rhizopus oryzae and Rhizopus arrhizus

“…Present results confirmed that a neutralizing agent such as CaCO 3 must be present in the fermentation media to achieve a maximum production of lactic acid by Rhizopus sp. The addition of CaCO 3 could neutralize H + released from lactic acid which may reduce the synthesis reaction forward to lactic acid production [21,22,24,25]. A significant improvement in terms of lactic acid and biomass production was obtained by addition of 1% CaCO 3 in the fermentation media.…”

“…R. oryzae NRRL 395 was extensively researched and has been recognized as one of the most suitable lactic acid producers [6,20,25]. The lactic acid production from 60 g/l to 80 g/l using R. oryzae NRRL 395 was obtained in more than 3-day batch process with a lactic acid yield between 65% and 78% [7,21,23,38]. The ability of Rhizopus to aerobically produce lactic acid under additional nutrient environment was studied [3,6,20,23,24,26].…”

“…Direct fermentation was successfully employed for lactic acid production from raw starch materials and many representative bacteria including Lactobacillus and Lactococcus species are used to produce lactic acid effectively [2,4,13,14,[16][17][18][19]. Lactic acid-producing fungi, such as Rhizopus oryzae, have recently received an interest in lactic acid production because of its low costs [2,3,6,[20][21][22][23]33]. Another two important aspects for using fungal lactic acid producer are that they can take a role to carry out this direct fermentation process as both enzyme and lactic acid producer, and may secrete L-lactic acid as the only fermentation product [3,6,20,[24][25][26][27].…”