Yuri Lee

Lactobacillus plantarum-mediated conversion of flavonoid glycosides into flavonols, quercetin, and kaempferol in Cudrania tricuspidata leaves

High value-added food materials were developed based on enhancement of phenolic contents in Cudrania tricuspidata leaves using fermentation of silkworm thorn leaves with Lactobacillus derived from Korean soybean paste. Ethanol extracts from fermentates were examined for antioxidant activities and flavonoid and corresponding glycoside contents. Radical scavenging activities were increased by approximately 20% after fermentation. Two prominent spectral peaks in fermentates that increased in size, compared with non-fermentates, were identified as quercetin (m/z 301.1) and kaempferol (m/z 285.3). Three peaks that decreased in size in fermentates were identified as quercetin-7-O-beta-glucopyranoside (m/z 463.1), kaempferol-3-O-beta-glucopyranoside (m/z 447.1), and kaempferol-7-O-beta-glucopyranoside (m/z 447.2). Conversion of flavonoid glycosides to flavonols, quercetin and kaempferol, occurred in silkworm thorn leaves due to fermentation with Lactobacillus.

Lactic acid bacteria-mediated fermentation of Cudrania tricuspidata leaf extract improves its antioxidative activity, osteogenic effects, and anti-adipogenic effects

The goal of this study was to assess the potential of fermented Cudrania tricuspidata leaf (CTL) aqueous extract as a functional food material. The CTL aqueous extract was fermented using lactic acid bacteria (LAB) isolated from soybean-fermented foods and the biological effects of the resultant fermented extracts on MG-63 human osteoblastic cells and 3T3-L1 mouse pre adipocytes were examined in vitro. We found that (1) the radical scavenging activities of CTL extracts fermented by various LAB strains (fermented CTL, F-CTL) were ~2- fold higher than that of non-fermented CTL extract (NFCTL), (2) F-CTL extract enhanced MG-63 cell proliferation compared to NF-CTL-treated cells, (3) the level of alkaline phosphatase activity in F-CTL-treated MG-63 cells was significantly higher than that in NF-CTL-treated cells, and (4) 3T3-L1 cell differentiation was dramatically decreased by F-CTL treatment, but not by NF-CTL. These findings suggest that CTL that has undergone LAB-mediated fermentation may be beneficial for promoting osteogenic differentiation of osteoblastic cells and inhibiting fat accumulation in adipocytes.

Optimization of cultivation medium and fermentation parameters for lincomycin production by Streptomyces lincolnensis

Production of lincomycin by Streptomyces lincolnensis was studied by varying medium composition and environmental conditions. With the medium composition optimized by statistical experimental design (45 g/L soluble starch, 15 g/L sugar cane molasses, 13.33 g/L peptone water, 6.67 g/L NaNO3 and 4.0 g/L CaCO3), lincomycin production increased by 2 ∼ 3 fold compared to that obtained with un-optimized basal medium. Lincomycin production was further improved by optimizing culture conditions such as agitation speed, impeller type and pH under the optimized medium condition. The highest titer of 350 mg/L lincomycin was achieved from 240 h bioreactor culture. These results demonstrate that fermentation conditions for maximal lincomycin production by Streptomyces lincolnensis were optimized via biotechnological processes.