Continuous production ofl-lactic acid from whey permeate by immobilizedLactobacillus casei subsp.casei

Abstract

The production of L-lactic acid from whey permeate, a waste product of the dairy industry, by fermentation with the lactic acid bacterium L a c t o b a c i l l u s casei subsp, casei was investigated. A fermentation medium consisting of permeate and supplements, which enables exponential growth of the organisms, was developed. A fast method for determination of free and immobilized biomass in solid-rich media, based on measurement of cellular ATP, was evolved. Continuous fermentations in a stirred tank reactor (STR) and in a fluidized bed reactor (FBR) with immobilized biomass were compared. In the STR a volumetric productivity of 5.5 g/1 per hour at 100% substrate conversion [dilution rate (D)---0.22 h -1] was determined. In the FBR porous sintered glass beads were used for immobilization and a maximum biomass concentration of 105 g/ kg support was measured. A productivity of 10 g/l per hour was obtained at D = 0.4 h-1 (substrate conversion 93%) and of 13.5 g/l per hour at D = 1.0 h -1 (substrate conversion 50%).

Production of Lactic Acid from Whey by Lactobacillus sp. Isolated from Local Dairy Products

“…However, at higher and lower pH levels, a decrease in the both the function was observed, with significant decrease at pH 6.0 and 7.0. A pH range of 6.0-6.5 has been reported optimal for lactic acid production using L. casei strain (Krischke et al, 1991). However, pH 5.5 has been used for lactic acid production using L. helveticus by (Ghaly et al, 2004).…”

“…L. helveticus, and L.acidophilus can be used in a temperature range of 37-45°C. Krischke et al, (1991) used 37°C temperature for lactic acid production using L. casei. However, a temperature of 28°C has also been reported optimal for L. casei in a separate study (Nabi et al, 2004).…”

Batch production of L(+) lactic acid from whey by Lactobacillus casei (NRRL B‐441)

“…Krischke et al 10 found that best growth and product formation occurred between pH 6.0 and 6.5 for immobilized L casei subsp casei grown on whey permeate. key factors in lactic acid fermentation.…”

“…For batch fermentation of whey permeate by L casei subsp casei, Krischke et al 10 concluded that the best growth comparable to MRS medium occurred with a combination of yeast extract (5 g dm −3 ) and hydrolyzed whey retentate (50 g dm −3 ). Guoqiang et al 12 determined that increasing yeast extract concentration (0-10 g dm −3 ) increased lactic acid production.…”

“…Fitzpatrick et al 16 and Krischke et al 10 have shown the beneficial effect of Mn 2+ for lactic acid production by L casei, due to its role as a constituent of lactate dehydrogenase.…”