Utilization of sugar molasses for economical l(+)-lactic acid production by batch fermentation of Enterococcus faecalis
ABSTRACT Lactic acid production from sugar molasses by batch fermentation of Enterococcus faecalis RKY1 was investigated in order to reduce the manufacturing cost of lactic acid. When the fermentation was carried out at pH 7.0, 95.7 g/l of lactic acid was obtained with a yield of 94.9% and productivity of 4.0 g/l h. Lactic acid fermentation using molasses was significantly affected by yeast extract concentrations. The maximum lactic acid productivity was obtained to 5.3 g/l h at 20 g/l of yeast extract. The final lactic acid increased with the increase of molasses concentrations, whereas the lactic acid productivity decreased probably due to substrate inhibition. When the medium containing 15 g/l of yeast extract was used, the maximum lactic acid concentration (134.9 g/l) and the maximum productivity (4.3 g/l h) were obtained at molasses concentrations of 333 g/l (equivalent to 170 g/l of total sugar) and 130 g/l (equivalent to 68 g/l of total sugar), respectively. In addition, l(+)-lactic acid content of lactic acid produced from molasses was above 98% in all cases experimented in this study.
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ABSTRACT: Sugarcane bagasses are one of the most extensively used agricultural residues. Using acid hydrolysis and fermentation, conversion of sugarcane bagasses to lactic acid was technically and economically feasible. This research was concerned with the solubility of lignin in ammonium hydroxide, acid hydrolysis and lactic acid fermentation by Lactococcus lactis, Lactobacillus delbrueckii, Lactobacillus plantarum, and Lactobacillus casei. The lignin extraction results for different ammonium hydroxide concentrations showed that 10 % (v/v) NH4OH was favorable to lignin dissolution. Acid hydrolysis can be enhanced with increasing acid concentration and reaction temperature. The optimum glucose and xylose concentrations occurred at 121 ○C for 1 hour hydrolysis time in 10% sulphuric acid solution were 32 and 11 g/l, respectively. In order to investigate the significance of medium composition on lactic acid production, experiments were undertaken whereby a culture of Lactococcus lactis was grown under various glucose, peptone, yeast extract and xylose concentrations. The optimum medium was composed of 5 g/l glucose, 2.5 g/l xylose, 10 g/l peptone and 5 g/l yeast extract. Lactococcus lactis represents the most efficient for lactic acid production amongst those considered. The lactic acid fermentation by Lactococcus lactis after 72 hours gave the highest yield of 1.4 (g lactic acid per g reducing sugar).World Journal of Engineering and Technology 01/2012; 66:173-178.
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ABSTRACT: The aim of this work was to study the capability of amylolytic of lactic acid bacteria to hydrolyze the onggok tapioca for lactic acid production. Of the three strains tested, Streptococcus bovis was selected. S. bovis was found to produce lactic acid directly from onggok substrate at pH 5.5. It has been demonstrated that lactic acid concentration as high as 39.98 g/l can be obtained from onggok-tofu liquid waste-20 g/l concentrates maguro waste. The yield and productivity of lactic acid in batch fermentation were 85% and 3.01 g/l.h, respectively.
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ABSTRACT: The feasibility of Micellar-Enhanced UltraFiltration (MEUF) is examined in this study for the recovery of lactic acid and citric acid from synthetic solutions at their natural pH (2.4–3.0) and from beet molasses previously pretreated with activated charcoal at pH=3. Several surfactants were assayed prior to the selection of sodium dodecyl sulphate (SDS). The affinity of SDS micelles for the extraction of organic acids was studied by centrifugal MEUF using 3 kDa regenerated cellulose membranes at 25 °C.Continuous crossflow MEUF was performed using a 5 kDa TiO2 tubular inorganic membrane at 30 °C. A two-parameter linear model, based on pseudophase equilibrium in aqueous solutions, was able to predict monomeric and micellar acid concentrations in both permeate and retentate. Simultaneous recovery of organic acids and removal of SDS for reuse was achieved by treatment of the retentate with sodium hydroxide and subsequent phase separation below the surfactant Krafft temperature.Crossflow MEUF of pretreated molasses was correctly simulated by the model previously developed with synthetic solutions. After the phase separation stage, 79.34% of lactic acid and 55.60% of citric acid contained in the pretreated molasses were recovered in the SDS-free supernatant, 95% of the SDS was separated in the solid phase for reuse and the remaining 5% of the SDS was collected in the permeate.Journal of Membrane Science 03/2013; 430:11-23. DOI:10.1016/j.memsci.2012.12.006 · 4.91 Impact Factor