• Journal of Dairy Science and Biotechnology
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• v.40 no.1
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• pp.15-22
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• 2022

This study evaluated the levels of D(-)-lactate and L(+)-lactate, and the ratio of D(-)-lactate to total lactate (D(-)-lactate + L(+)-lactate) of 15 lactic acid bacteria (LAB) using an enzymatic method. D(-)-lactate and L(+)-lactate levels in the LAB ranged from 0.31 to 13.9 mM and 0.76 to 39.3 mM, respectively, in Bifidobacterium sp.; 1.08 to 11.7 mM and 0.69-13.0 mM in Lactobacillus sp.; 0.72 to 20.3 mM and 0.98 to 32.3 mM in Leuconostoc sp., and 33.0 mM and 39.2 mM in Pediococcus acidilacti KCCM 11747. The ratio of the range of D(-)-lactic acid to total lactic acid was 28.98%-45.76% in Bifidobacterium sp., 41.18%-61.02% in Lactobacillus sp., 29.85%-42.36% in Leuconostoc sp., and 45.71% in P. acidilacti KCCM 11747. In the future, there is a need to test for D(-)-lactate in various fermented products to which different LAB have been added and study the screening of LAB used as probiotics that produce various concentrations of D(-)-lactate.

• Reproductive and Developmental Biology
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• v.34 no.4
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• pp.299-304
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• 2010

To identify the treatment effect of lactic acid bacteria for diabetes, the treatment effects of a single administration of acarbose (a diabetes treatment drug) or lactic acid bacteria, and the mixture of acarbose and lactic acid bacteria on diabetes in a type 1 diabetes animal model, were studied. In this study, streptozotocin was inoculated into a Sprague-Dawley rat to induce diabetes, and sham control (Sham), diabetic control (STZ), STZ and composition with live cell, STZ and composition with heat killed cell, STZ and composition with drugs (acarbose) were orally administered. Then the treatment effect on diabetes was observed by measuring the body weight, blood glucose, and serum lipid. For the histopathological examination of the pancreas, the Langerhans islet of the pancreas was observed using hematoxylin and eosin staining, and the renal cortex, outer medullar, and inner medullar were also observed. The induced diabetes decreased the body weight, and the fasting blood glucose level decreased in the lactic-acid-bacteria-administered group and the mixture-administered group. In addition, the probiotic resulted in the greatest decrease in the serum cholesterol level, which is closely related to diabetes. Also, the hematoxylin and eosin staining of the Langerhans islet showed that the reduction in the size of the Langerhans islet slowed in the lactic-acid-bacteria-administered group. The histopathological examination confirmed that the symptoms of diabetic nephropathy decreased in the group to which viable bacteria and acarbose were administered, unlike in the group to which dead bacteria was administered. The mixture of lactic acid bacteria and acarbose and the single administration of lactic acid bacteria or acarbose had treatment effects on the size of the Langerhans islet and of the kidney histopathology. Thus, it is believed that lactic acid bacteria have treatment effects on diabetes and can be used as supplements for the treatment of diabetes.

• Microbiology and Biotechnology Letters
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• v.22 no.3
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• pp.277-282
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• 1994

In batch cultures of Lactobacillus delbrueckii, cell growth and lactic acid production were affected by two main factors, inhibition by lactic acid and limitation by nutritional components. In order to increase th productivity significantly, a continuous stirred tank reactor with cell recycle was employed. A cell desnity of 145g dry weight/l and a volumetric productivity of 73 g/l$\cdot $h were obtained with an effluent concentration of 85 g/l lactic acid. The productivity achieved by this system was 23-fold higher than those obtained by the corresponding batch cultivations. Once the lactic acid concentration reached the steady steady state, lowering the yeast extract concentration caused the reduction of the lactic acid concentration without affection the biomass concentration. Finally, the formation of D-lactate was investgated. During the various cultures, a small amount of D-lactate always formed, even thought a majority of lactate was L-isomer, It was supposed that the relative amount of the D-lactate was affected by glucose limitation, and there seems to exist a certain relationship between the concentration of D-lactate and acetate.

• KSBB Journal
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• v.31 no.1
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• pp.85-89
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• 2016

Lactic acid fermentations were conducted using water hyacinth. It is known that the pretreatment and enzyme hydrolysis process optimize the potential of water hyacinth. Lactic acid produced by using lactic acid bacteria. All cells were grown at $37^{\circ}C$ and initial pH 5.5. Lactic acid production was measured by HPLC. All Lactobacillus strains could produce lactic acid from pretreated water hyacinth. The highest lactic acid was achieved when lactic acid fermentation was carried out by L. delbrueckii for D-form and L. helveticus for L-form lactic acid production. The lactic acid concentration was 10.70 g/L by L. delbrueckii and it converted glucose in the medium to lactic acid, almost perfectly. Lactic acid production became higher when fermentation was carried out at a controlled pH 5.5. Lactic acid yield and productivity were 0.52 g/g and 0.19 g/L/h for L. helveticus, while L. delbrueckii was 0.64 g/g and 0.27 g/L/h. This study showed that water hyacinth medium could be alternative medium which can replace the complex and expensive medium for growing Lactobacillus strains in production of lactic acid.

• KSBB Journal
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• v.27 no.3
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• pp.151-156
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• 2012

Lactic acid is an important product arising from the anaerobic fermentation by lactic acid bacteria (LAB). It is used in the pharmaceutical, cosmetic, chemical, and food industries as well as for biodegradable polymer and green solvent production. The poly lactic acid (PLA) is an important material for bio-plastic manufacturing process. For PLA production by new LAB, we screened LAB isolates from shellfish. A total of 28 LAB were isolated from various shellfishes. They were all Gram positive, oxidase and catalase negative. Based on API 50CHL kit, 7 strains among the 28 isolates were identified as Lactobacillus plantarum, 6 strains as Lactobacillus delbrueckii, 5 strains as Leuconostoc mesenteroides, 3 strains as Lactobacillus brevis, 2 strains as Lactococcus lactis, 1 strain as Lactobacillus salivarius, 1 strain as Lactobacillus paracasei, 1 strain as Lactobacillus pentosus, 1 strain as Lactobacillus fermentum and 1 strain as Pediococcus pentosaceu. Also, we examined the amount of total lactic acid produced by these new strains by HPLC analysis with Chiralpak MA column. One strain E-3 from Mytilus edulis was indentified as Lactobacillus plantarum and found to produce 20.0 g/L of D-form lactic acid from 20 g/L of dextrose. Further studies are underway to increase the D-lactic acid production by E-3.

• Macromolecular Research
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• v.17 no.9
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• pp.682-687
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• 2009

Nanofibrous membranes of poly(D,L-lactic acid)/chitin blend were prepared by electro spinning for a barrier of guided tissue regeneration. A miscible solution was obtained by the blending chitin-salt complex into 1-methyl-2-pyrrolidone solution of poly(D,L-lactic acid). The properties of the blend were examined for nanofibrous fabrication. The viscosity of the blend solution was increased significantly due to chain entanglement despite the low ratio of chitin to poly(D,L-lactic acid). An interaction between two polymeric compositions was confirmed by Fourier transform infrared spectroscopy. X-ray diffraction detected an appreciably ordered microstructure in the nanofiber of the blend. A membrane of thinner nanofibers was fabricated by electro spinning the chitin blend. The permeability of the membranes was examined using bioactive model compounds.

• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.482-486
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• 1996

Batch fermentations of lactic acid were performed with Lactobacillus casei to investigate the effect of pH on cell growth and production of lactic acid and by-products. Maximum productivity of lactic acid increased with increasing pH from 5.0 to 6.5, and the extent of D-lactate production was different at each pH. Acetate and D-lactate concentrations increased even after the complete consumption of glucose in the medium. While a pH range of 6.0-6.5 was optimal for cell growth and lactic acid production, superior results were achieved at pH 6.0 when both maximum lactic acid productivity and minimum by-product formation were considered.

• KSBB Journal
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• v.17 no.4
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• pp.333-338
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• 2002

This study was targeted to isolate and characterize a bacterium producing lactic acid in a large amount. Lactic acid bacteria of about fifty strains were isolated from kimchi, a Korean traditional fermented vegetable food. Strain KH-1 of them was most effective in the lactic acid production and showed 99% homology with Lactobacillus casei from analysis of 16S rRNA sequencing. The conversion ratio of lactic acid from glucose by 1. casei KH-1 was 98% in anaerobic condition, and the lactic acid was composed as racemic mixture of D(-)-and L(+)-lactic acid, 7% and 93%, respectively. This result indicated that L. casei KH-1 was a homofermentative bacterium mainly producing L(+)-lactic acid. The strain KH-1 used glucose as a preferential substrate but not utilized lactose. In investigation of more inexpensive nitrogen source for cultivation of strain KH-1 using industrial MRS medium, when yeast extract and corn steep liquor were used at the ratio of 1 to 1, the molar yield of lactic acid produced per mole of glucose(Yp/s) was 1.09.

• Journal of Pharmaceutical Investigation
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• v.26 no.1
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• pp.13-22
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• 1996

Poly(D,L-lactic acid) (PLA) microspheres containing alprazolam(APZ) were prepared by a solvent-emulsion evaporation method and their release patterns were investigated in vitro. Various batches of microspheres with different size and drug content were obtained by changing the ratio of APZ to PLA, PLA concentration in the dispersed phase and stirring rate. Rod-like APZ crystals on microsphere surface, which were released rapidly and could act as a loading dose, were observed with increasing drug content. The release rate was increased with increase in drug contents and decrease in the molecular weight of PLA. The release rate of APZ for long-acting injectable delivery system in vitro, which would aid in predicting in vitro release profile, could be controlled by properly optimizing various factors affecting characteristics of microspheres.

• KSBB Journal
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• v.30 no.4
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• pp.161-165
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• 2015

Lactic acid and its derivatives are widely used in the food, pharmaceutical, and cosmetic industries. It is also a major raw material for the production of poly-lactic acid (PLA), a biodegradable and environmentally friendly polymer and a possible alternative to synthetic plastics derived from petroleum. For PLA production by new strains of lactic acid bacteria (LAB), we screened LAB isolates from shellfish. A total of 51 LAB were isolated from 7 types of shellfishes. Lactic acid production of individual isolates was examined using high-performance liquid chromatography using a Chiralpak MA column and an ultraviolet detector. Lactobacillus plantarum T-3 was selected as the most stress-resistant strain, with minimal inhibition concentrations of 1.2 M NaCl, 15% ethanol, and 0.0020% hydrogen peroxide. In a 1 L fermentation experiment, $\small{D}$-lactic acid production of 19.91 g/L fermentation broth was achieved after 9 h cultivation, whereas the maximum production of total lactic acid was 41.37 g/L at 24 h.