Abstract: The present invention relates to a method for the biocatalytic synthesis of substituted and unsubstituted phenylacetic acids and ketones from styrenes and bicyclic aromatic hydrocarbons using enzymes of microbial styrene degradation in a whole-cell sensor, as well as a kit for the biocatalytic synthesis of substituted and unsubstituted phenylacetic acids and ketones containing a whole-cell catalyst and the use of the method, wherein the method comprises the following steps: a) providing at least one type of whole-cell catalyst, containing genes which code for the enzymes of styrene degradation and are under the functional control of a regulatable promoter, in an aqueous component, b) activating the whole-cell catalyst with an inducer and/or an activator, leading to expression of the gene, c) bringing the activated whole-cell catalyst into contact with a substrate, d) isolating the reaction products produced, which are advantageously not further metabolized by the whole-cell cat and advantageously accumulat