New biosensor method as a first step in assessing microbial metabolism: Case study of Rhodococcus methylotrophy

Abstract

The new simple and easy-to-use electrochemical biosensor method has not been previously used to assess the growth substrate for Rhodococcus methylotrophs. This method implies the combined use of laboratory models of microbial sensor devices to evaluate the constitutiveness and inducibility of enzymes of the initial metabolism of substrate. Earlier, two facultative methylotrophs were compared using traditional methods: Rhodococcus wratislaviensis VKM Ac-2782 was able to grow in the methanol-containing medium, no growth of Rhodococcus koreensis DNP505^T was observed. In this study, using the biosensor approach, it was shown that differences in growth of cultures were due to the presence/absence of the enzyme of the initial metabolism of methanol. The existence of the constitutive enzyme of the initial metabolism of methanol predetermined the growth of R. wratislaviensis in the presence of methanol. Methanol penetrated into R. koreensis cells; but the culture did not contain the enzyme for the first stage of methanol metabolism. As a result, R. koreensis did not grow in the methanol-containing medium. The obtained results confirm that the new biosensor method is an indispensable tool for assessing the availability of substrate for microbial cultures, significantly facilitating research in the field of taxonomy, microbial bioremediation and fermentation of microorganisms.