# Naturally Occurring Flavonoids and Isoflavonoids and Their Microbial Transformation: A Review
## 3 Microbiological Transformation of Isoflavonoids and Flavonoids
### Biotransformation of Isoflavones and Flavonoids by Fungi
Compound **102**, 6-hydroxyflavone, was metabolized by strain KCH J2 in 5 days to produce 6-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)- glucopyranoside (**160**) with 13% yield. Compound **160** was obtained when _I. farinosa_ KW1.2 was used as a biocatalyst. 7-Hydroxyflavone (**121**) was metabolized by strain KCH J2 in 7 days to produce 7-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)-glucopyranoside (**161**) with 16% yield. Compound **161** was additionally obtained when both of the strains J1.4 and J1.6 were used as a biocatalyst. Daidzein (**1**) was metabolized by strain KCH J2 in 7 days to obtain 4\({}^{\prime}\)-hydroxyisoflavone 7-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)- glucopyranoside (4\({}^{\prime\prime}\)-O-methyldaidin) (**162**) with 14.8% yield. Compound **162** was also obtained when strains KW1.2 and J1.6 were used as biocatalyst. 7-Aminoflavone (**163**) was metabolized by strain KCH J2 in 7 days to obtain 7-acetamidoflavone (**164**) with 10% yield and 4\({}^{\prime}\)-hydroxy-7-acetamidoflavone (**165**) with 3% yield [82]. There is a similar report about _I. fumosorosea_ KCH J2. 2\({}^{\prime}\)-Methoxyflavanone (**166**) was transformed in the broth of the strain KCH J2 to 2\({}^{\prime}\)-methoxyflavanone 5\({}^{\prime}\)-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)-glucopyranoside (**167**) with 18.6% yield and flavan-4-ol 2\({}^{\prime}\)-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)-glucopyranoside (**168**) with 24.9% yield after 11 days of biotransformation. 3\({}^{\prime}\)-Methoxyflavanone (**169**) was metabolized by strain KCH J2 in 7 days to produce flavan-4-ol 3\({}^{\prime}\)-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)-glucopyranoside (**170**) with a yield of 15.4% and 3\({}^{\prime}\)-hydroxyflavanone 6-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)-glucopyranoside (**171**) with a yield of 16%. 4\({}^{\prime}\)-Methoxyflavanone (**172**) was metabolized by strain KCH J2 in 7 days to produce 4\({}^{\prime}\)-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)-glucopyranoside (**173**), 4\({}^{\prime}\)-hydroxyflavanone 6-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)-glucopyranoside (**174**) and 3\({}^{\prime}\),4\({}^{\prime}\)-dihydroxyflavanone 6-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)-glucopyranoside (**175**) with the yields of 11%, 20.7% and 32.8%, respectively. 6-Methoxyflavanone (**120**) was metabolized by strain KCH J2 in 8 days to produce 6-methoxyflavanone 4\({}^{\prime}\)-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)-glucopyranoside (**176**), and 3\({}^{\prime}\)-hydroxy-6-methoxyflavanone-4\({}^{\prime}\)-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)-glucopyranoside (**177**) with the yields of 6% and 7%, respectively. Compound **118** was metabolized by the strain KCH J2 in 12 days to produce 6-methoxyflavanone 3\({}^{\prime}\)-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)-glucopyranoside (**178**), 6-methoxyflavone 4\({}^{\prime}\)-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)-glucopyranoside (**179**), and 3\({}^{\prime}\)-hydroxy-6-methoxyflavone 4\({}^{\prime}\)-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)-glucopyranoside (**180**) with yields of 2.6%, 7.8%, and 7.9%, respectively [83]. When _I. fumosorosea_ KCH J2 as the biocatalyst, the substrate 3-hydroxyflavone (**98**) was metabolized in 7 days to produce flavone 3-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)-glucopyranoside (**181**), flavone 3-O-\(\beta\)-D-glucopyranoside (**182**), and 3-O-[\(\beta\)-D-glucopyranoside(1-\(\to\)6\()\)-\(\beta\)-D-glucopyranoside]-4\({}^{\prime}\)-hydroxyflavone (**183**) with the conversion rates of 42.5%, 5%, and 3.5%, respectively. Compounds **181** and **182** were formed by the biocatalysis of the strains J1.4 and J1.6. Besides, 3-methoxyflavone 4\({}^{\prime}\)-O-\(\beta\)-D-(4\({}^{\prime\prime}\)-O-methyl)-glucopyranoside (**185**) was obtained with 29% yield from the transformation of 3-methoxyflavone (**184**) in the culture of strain KCH J2 for 7 days.