Synthesis of hydroxytyrosol, 2-hydroxyphenylacetic acid, and 3-hydroxyphenylacetic acid by differential conversion of tyrosol isomers using Serratia marcescens strain.
We investigated to develop an effective procedure to produce the potentially high-added-value phenolic compounds through bioconversion of tyrosol isomers. A soil bacterium, designated Serratia marcescens strain, was isolated on the basis of its ability to grow on p-tyrosol (4-hydroxyphenylethanol) as a sole source of carbon and energy. During growth on p-tyrosol, Ser. marcescens strain was capable of promoting the formation of hydroxytyrosol. To achieve maximal hydroxytyrosol yield, the growth state of the culture utilized for p-tyrosol conversion as well as the amount of p-tyrosol that was treated were optimized. The optimal yield of hydroxytyrosol (80%) was obtained by Ser. marcescens growing cells after a 7-h incubation using 2 g/L of p-tyrosol added at the end of the exponential phase to a culture pregrown on 1 g/L of p-tyrosol. Furthermore, the substrate specificity of the developed biosynthesis was investigated using m-tyrosol (3-hydroxyphenylethanol) and o-tyrosol (2-hydroxyphenylethanol) as substrates. Ser. marcescens strain transformed completely m-tyrosol and o-tyrosol into 3-hydroxyphenylacetic acid and 2-hydroxyphenylacetic acid, respectively, via the oxidation of the side chain carbon of the treated substrates. This proposed procedure is an alternative approach to obtain hydroxytyrosol, 2-hydroxyphenylacetic acid, and 3-hydroxyphenylacetic acid in an environmentally friendly way which could encourage their use as alternatives in the search for replacement of synthetic food additives.
Allouche
Noureddine
N
Laboratoire des Bio-Procédés, Centre de Biotechnologie de Sfax B.P K. 3038, Sfax, Tunisia.
Sayadi
Sami
S
D007700:Kinetics; D010648:Phenylacetates / Q000378:metabolism*; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000378:metabolism; D012706:Serratia marcescens / Q000378:metabolism*; D012988:Soil Microbiology
D010648:Phenylacetates; C005975:3,4-dihydroxyphenylethanol; C011867:4-hydroxyphenylethanol; C008069:3-hydroxybenzeneacetic acid; D010626:Phenylethyl Alcohol; C005756:2-hydroxyphenylacetic acid