Biotransformation and recovery of the isoflavones genistein and daidzein from industrial antibiotic fermentations

Abstract

The objective of this study was to follow the metabolic fate of isoflavone glucosides from the soybean meal in a model industrial fermentation to determine if commercially useful isoflavones could be harvested as coproducts from the spent broth at the end of the fermentation. The isoflavone aglycones, genistein and daidzein, together make up 0.1 - 0.2% of the soybean meal by weight but serve no known function in the manufacturing process. After feeding genistein to washed cells of the erythromycin-producing organism, Saccharopolyspora erythraea, the first biotransformation product (Gbp1) was determined by x-ray crystallography to be genistein-7-O-α-rhamnoside (rhamnosylgenistein). Subsequent feeding of rhamnosylgenistein to growing cells of S. erythraea led to the production of a second biotransformation product, Gbp2. Chromatographic evidence suggested that Gbp2 accumulated in the spent broth of the erythromycin fermentation. When the spent broth was hydrolyzed with acid or industrial enzyme preparations the isoflavone biotransformation products were returned back to their parental forms, genistein and daidzein, which were then recovered as coproducts. Desirable features of this method are that it does not require modification of the erythromycin manufacturing process or genetic engineering of the producing organism to be put into practice. A preliminary investigation of five additional antibiotic fermentations of industrial importance were also found to have isoflavone coproduct potential.

Eurotium Cristatum Fermented Okara as a Potential Food Ingredient to Combat Diabetes

“…Moreover, the microbial biotransformation of okara can cause a major reduction in the glucoside, malonylglucoside and acetylglucoside isoflavones along with a significant increase of aglycone isoflavones content. The aglycone isoflavones (daidzein, genistein and glycitein) are absorbed faster and in higher amounts than their glucosides in humans, and hence the increase of bioavailability of these isoflavones will potentially improve the antidiabetic effects 11,12 . Liu et.…”

Polyhalogenation of Isoflavonoids by the Termite-Associated Actinomadura sp. RB99

“…The combined results were surprising at first, as isoflavonoid-based natural products are typical plant-derived metabolites and biosynthesized via a biosynthetic branch of the phenylpropanoid pathway. , A few bacterial lineages, most notable Streptomyces , are able to produce the flavonoid naringenin, but subsequent conversion to isoflavones is unique to plants. − Thus, we hypothesized that isoflavones, such as daidzein and genistein, are present within the provided growth medium (ISP2) and then biotransformed by RB99 to polyhalogenated derivatives (Scheme ). , To support the hypothesis, we analyzed the applied ISP2 medium, and it was confirmed by HRMS 2 and GNPS analysis that both plant-derived metabolites are present in solid-phase extracts of sterile ISP2 medium (Figures and S3).…”

“…Together with an isolated distinctive olefinic proton at δ H 8.24 (1H, s), it was deduced that 1 is built from an isoflavonoid scaffold, which was supported by a distinct flavonoid/isoflavonoid-type UV spectrum (λ max 222, 250, and 298 nm). − The 13 C NMR data of 1 , assigned based on the analysis of 2D NMR ( 1 H– 1 H COSY, HSQC, and HMBC) spectra, indicated the presence of 15 carbon signals (mostly aromatic), including one carbonyl group at δ C 177.0. Comparative 1 H and 13 C NMR analysis using an available in-house database and SciFinder confirmed that compound 1 closely resembled 3′,4′,5′,7-tetrahydroxyisoflavone (Figure ) and was of symmetric nature [δ H 7.52 (2H, s); δ C 129.8 (C-2′/C-6′)] .…”

Release of Soybean Isoflavones by Using a β‐Glucosidase from Alicyclobacillus herbarius

“…Soy isoflavones are released as a side‐product during the industrial fermentation process for the production of erythromycin, using the microorganism Saccharopolyspora erythraea (by endogenous β‐glucosidases). However, the isoflavone aglycones themselves are metabolised by that organism, requiring either metabolic engineering or subsequent enzymatic treatment (or acid hydrolysis) of the spent broth to obtain the aglycon [12–14] . The use of purified β‐glucosidases for isoflavone aglycon production from soy flour has also been investigated, in particular from the thermophilic bacteria Thermotoga maritima and Thermoanaerobacter ethanolicus JW200.…”

“…However, the isoflavone aglycones themselves are metabolised by that organism, requiring either metabolic engineering or subsequent enzymatic treatment (or acid hydrolysis) of the spent broth to obtain the aglycon. [12][13][14] The use of purified β-glucosidases for isoflavone aglycon production from soy flour has also been investigated, in particular from the thermophilic bacteria Thermotoga maritima and Thermoanaerobacter ethanolicus JW200. However, these enzymes required defatting of the soy flour using hexane (an undesirable neurotoxic solvent [15] ) and high reaction temperatures (65-80 °C).…”