Glycerol catabolism by Pediococcus pentosaceus isolated from beer

VIZOSO PINTO, M. G.; PASTERIS, S. E.; STRASSER DER SAAD, A. M.

FOOD MICROBIOLOGY

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Año: 2004 vol. 21 p. 111 - 118

0740-0020

Among the lactic acid bacteria isolated from beer at different stages of elaboration, Pediococcus  pentosaceus was the predominant species and the only that used glycerol as sole carbon source. Its utilization was studied in CAg  strain growing on glycerol or on glycerol and limited concentration of glucose. Glycerol kinase and glycerol dehydratase  pathways were responsible for glycerol degradation. On glycerol alone,the enzymatic activities of both pathways were expressed  simultaneously and after glycerol consumption, the main products were acetate, 2,3-butanediol (2,3-BD) and 1,3-propanediol  (1,3-PD). When the carbon sources were glycerol and glucose,glycerol was firstly degraded by the reductive pathway and after  glucose consumption the activities of the glycerol kinase pathway were expressed. In this condition, glycerol was transformed into lactate,  acetate, 2,3-BD and 1,3-PD. According to the enzymatic activities and fermentation balances,the production of  acetate,providing ATP, can be correlated to lactate degradation, and the NAD required by these transformations could be obtained by the  formation of 1,3-PD and 2,3-BD. Glycerol degradation should be correlated with the sensitivity of a beer to bacterial spoilage,and P. pentosaceus CAg consideredas spoilage strain because it produces high volatile acidity and aroma compounds from glycerol  conferring unacceptable flavour to beer.