• Journal of Microbiology and Biotechnology
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• v.29 no.6
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• pp.897-904
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• 2019

Monascus purpureus recombinant mppC and mpp7 knockout strains were subjected to extractive fermentation in the context of azaphilone pigment production. Inclusion of Diaion HP-20 resin resulted in the selective production of unreduced azaphilone congeners, in addition to the early intermediate FK17-P2a, from ${\Delta}mppC$ and ${\Delta}mpp7$ strains that would otherwise mainly produce reduced congeners. Structural determination of two novel unreduced azaphilones from the ${\Delta}mpp7$ strain was accomplished. The unreduced azaphilone compound was converted into the cognate reduced congener in recombinant M. purpureus strains, demonstrating its intermediate role in azaphilone biosynthesis. This study demonstrates the possibility that extractive fermentation with Diaion HP-20 resin can be used to obtain cryptic azaphilone metabolites.

• Molecules and Cells
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• v.44 no.2
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• pp.68-78
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• 2021

Secondary metabolites enable plants to protect themselves from herbivorous insects. Among these, cucurbitacin B (cuc-B) is a bitter-tasting compound with promising pharmacological potential. Dietary exposure to cuc-B lowered the hemolymph glucose levels of Drosophila melanogaster fed with a high carbohydrate diet, which is homologous to high blood glucose in humans, and its effect was comparable to that of metformin, a well-known glucose-lowering drug. Furthermore, cuc-B reduced tissue sugar levels and glycogen levels, as well as triacylglycerol levels. Our results thus highlight the potential applicability of this compound to treat chronic metabolic diseases such as diabetes and obesity. Additionally, we analyzed sleep quality and taste-associative memory enhancement after cuc-B and metformin treatment. Both supplements increased nighttime bout length and metformin increased memory consolidation. Therefore, discarded shell of Cucurbitaceae could be processed into health supplements.

• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.217-226
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• 2015

Metabolite profiles of seven commercial vinegars and two traditional vinegars were performed by gas chromatography time-of-flight mass spectrometry with multivariate statistical analysis. During alcohol fermentation, yeast, nuruk, and koji were used as sugars for nutrients and as fermentation substrates. Commercial and traditional vinegars were significantly separated in the principal component analysis and orthogonal partial least square discriminant analysis. Six sugars and sugar alcohols, three organic acids, and two other components were selected as different metabolites. Target analysis by ultra-performance liquid chromatography quadruple-time-of-flight mass spectrometry and liquid chromatography-ion trap-mass spectrometry/mass spectrometry were used to detect several metabolites having antioxidant activity, such as cyanidin-3-xylosylrutinoside, cyanidin-3-rutinoside, and quercetin, which were mainly detected in Rural Korean Black raspberry vinegar (RKB). These metabolites contributed to the highest antioxidant activity measured in RKB among the nine vinegars. This study revealed that MS-based metabolite profiling was useful in helping to understand the metabolite differences between commercial and traditional vinegars and to evaluate the association between active compounds of vinegar and antioxidant activity.

• Journal of Applied Biological Chemistry
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• v.57 no.1
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• pp.41-45
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• 2014

In the present study, red ginseng extracts were fermented by Paecilomyces tenuipes and the protopanaxdiol-type ginsenosides in the extracts were bio-transformed to F2, Rg3, Rg5, Rk1, Rh2, and CK determined by a high-pressure liquid chromatography analysis. It indicates that P. tenuipes is a microorganism to biotransform protopanaxdiol-type ginsenosides to their less glucosidic metabolites. Other biotransformed metabolites during fermentation were also analyzed using a GC-MS and identified as 2-methyl-benzaldehyde, 4-vinyl-2-methylphenol, palmitic acid, and linoleic acid. Antiulcerogenic activity of the fermented red ginseng extract (FRGE) on gastric mucosal damage induced by 0.15 M HCl in ethanol in rats was evaluated. FRGE was shown to have a potent protective effect on gastritis with 60.5% of inhibition rate at the dose of 40 mg/kg when compared to 54.5% of the inhibition rate at the same dose for stillen, the currently used medicine for treating gastritis. Linoleic acid showed a strong inhibition on gastritis with 79.3% of inhibition rate at the dose of 40.0 mg/kg. FRGE exhibited a distinct anticancer activity including growth inhibition of the two human colon cancer cells HT29 and HCT116. HT29 cells were less susceptible to FRGE in comparison with HCT116 cells. Taken together, fungal fermentation of the red ginseng extract induced hydrolysis of some ginsenosides and FRGE exhibited potent antiulcerogenic and anticancer activities. These results refer to use FRGE as a new source for treating human diseases.

• Journal of Food Hygiene and Safety
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• v.35 no.5
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• pp.419-429
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• 2020

The problems caused by foodborne pathogens are not only a concern to the food industry but also with regard to global public health. Over the years, fermentation technology has proved to be one of the cheapest and safest methods for inactivating and controlling pathogenic microorganisms in food. Scientific evidence shows that lactic acid bacteria fermentation exerts significant antimicrobial effect against pathogenic bacteria and viruses. Lactic acid bacteria metabolites such as organic acids, bacteriocins and hydrogen peroxides have adverse effects on foodborne pathogens which lead to their inhibition. These compounds do not only cause physical injuries, but also have significant effects on the pathogens' gene expression. Furthermore, the presence of lactic acid bacteria in food provides nutritional competition among foodborne pathogens, and all these factors together suppress their growth. This study reviews our current knowledge of the antimicrobial abilities of lactic acid bacteria, their molecular mechanisms, and their application for inactivating foodborne pathogens.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.6
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• pp.797-805
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• 2014

The effect of concentrate mixtures with crude protein (CP) levels 10%, 13%, 16%, and 19% and diets with roughage to concentrate ratios 80:20, 60:40, 40:60, and 20:80 (w/w) were determined on dry matter (DM) and organic matter (OM) digestibility, and fermentation metabolites using an in vitro fermentation technique. In vitro fermented attributes were measured after 4, 24, and 48 h of incubation respectively. The digestibility of DM and OM, and total volatile fatty acid (VFA) increased whereas pH decreased with the increased amount of concentrate in the diet (p<0.001), however CP levels of concentrate did not have any influence on these attributes. Gas production reduced with increased CP levels, while it increased with increasing concentrate levels. Ammonia nitrogen ($NH_3$-N) concentration and microbial CP production increased significantly (p<0.05) by increasing CP levels and with increasing concentrate levels in diet as well, however, no significant difference was found between 16% and 19% CP levels. Therefore, 16% CP in concentrate and increasing proportion of concentrate up to 80% in diet all had improved digestibility of DM and organic matter, and higher microbial protein production, with improved fermentation characteristics.

• Natural Product Sciences
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• v.21 no.4
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• pp.261-267
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• 2015

Compared to their terrestrial and marine counterparts, little is known about the capacity of freshwater-derived actinomycete bacteria to produce novel secondary metabolites. In the current study, we highlight the disparities that exist between cultivation-independent and -dependent analyses of actinomycete communities from four locations in Lake Michigan sediment. Furthermore, through phylogenetic analysis of strains isolated from these locations, we identified a Streptomyces sp., strain B025, as being distinct from other Streptomyces spp. isolated from sediment. Upon fermentation this strain produced a rare class of eight-membered lactone secondary metabolites, which have been for their antitumor properties. We used spectroscopic and chemical derivitization techniques to characterize octalactin B (1) in addition to its corresponding novel, unnatural degradation product (2).

• Natural Product Sciences
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• v.23 no.4
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• pp.306-309
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• 2017

Microbial transformation of $({\pm})$-6-(1,1-dimethylallyl)naringenin (6-DMAN, 1) and $({\pm})$-5-(O-prenyl) naringenin-4',7-diacetate (5-O-PN, 2) was performed by using fungi. Scale-up fermentation studies with Mucor hiemalis, Cunninghamella elegans var. elegans, and Penicillium chrysogenum led to the isolation of five microbial metabolites. Chemical structures of the metabolites were determined by spectral analyses as $({\pm})$-8-prenylnaringenin (3), (2S)-5,4'-dihydroxy-7,8-[(R)-2-(1-hydroxy-1-methylethyl)-2,3-dihydrofurano]flavanone (4), $({\pm})$-5-(O-prenyl)naringenin-4'-acetate (5), $({\pm})$-naringenin-4'-acetate (6), and $({\pm})$-naringenin (7), of which 5 was identified as a new compound.

• KSBB Journal
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• v.32 no.3
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• pp.238-244
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• 2017

Antioxidant activities of blackberry juice and aronia juice were enhanced when fermentation was performed by acetic acid bacteria. Acetobacter pasteurianus exhibited 19.84% improvement of antioxidant activity (from $198.12{\pm}2.03$ to $237.42{\pm}7.32{\mu}mol\;TE/g$) after 12 h fermentation of blackberry juice among four acetic acid bacteria. And A. pasteurianus sub sp. Pasteurianus exhibited 9.62% improvement of antioxidant activity (from $204.25{\pm}3.98$ to $223.89{\pm}5.52{\mu}mol\;TE/g$) after 12 h fermentation of aronia juice. Metabolites of blackberry juice were analyzed to investigate the enhancement of antioxidant activity before and after fermentation. As results, Quercetin 7-(rhamnosylglucoside), nicotinic acid adenine dinucleotide, and quercetin 3-O-(6"-acetyl-glucoside) were significantly increased after fermentation by A. pasteurianus.

• Journal of Microbiology and Biotechnology
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• v.32 no.4
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• pp.473-483
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• 2022

In this study we investigated the effect of lactic acid bacteria (LAB) fermentation on the ingredients and anti-oxidant activity of Withania somnifera extract. Four strains of LAB could proliferate normally in medium containing W. somnifera extract after the pH reached 3.1~3.5. LAB fermentation increased the content of alcohols and ketones, endowing the extract with the characteristic aroma of fermentation. Compared to the control, the DPPH and ABTS free radical scavenging rates in the fermented samples were significantly improved, ranging from 48.5% to 59.6% and 1.2% to 6.4%. The content of total phenols was significantly increased by 36.1% during the fermentation of mixed bacteria. Moreover, the original composition spectrum of the extract was significantly changed while the differentially accumulated metabolites (DAMs) were closely related to bile secretion, tryptophan metabolism and purine metabolism. Therefore, LAB fermentation can be used as a promising way to improve the flavor and bioactivity of the extracts of W. somnifera, making the ferments more attractive for use as functional food.