There is a growing interest in exploiting microbial bioconversions for the production of high value-added products such as vanillin and vanillic acid. We conducted this study to screen strains of bacteria which are able to degrade ferulic acid, and to evaluate the possibility of forming vanillic acid via conversion of ferulic acid under resting cell conditions. Twenty-seven different strains of bacteria were isolated from different samples which in turn were collected from a variety of sites in Iran and examined for bioconversion of ferulic acid into vanillic acid by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) analyses. Based on TLC and HPLC analyses, the strain SHL1 giving highest vanillic acid yield was selected and identified as Bacillus licheniformis (GenBank accession number HQ111516) based on morphological and physiochemical characteristics and its 16S rDNA gene sequence. In the presence of 1 g/l ferulic acid, vanillic acid reached a maximum value of 494 mg/l (molar yield of 60%) after 45 h of reaction time using resting cells of strain SHL1 without further optimization. The present study gives the first evidence for ferulic acid biotransformation by B. licheniformis.
