LACTIC ACID PRODUCTION IN A ccpA MUTANT OF Lactobacillus casei

MARIANA C ALLIEVI; MARÍA MERCEDES PALOMINO; MARIANO PRADO ACOSTA; CARMEN SANCHEZ RIVAS; SANDRA M RUZAL

Villa Carlos Paz

Congreso; XLIV Reunión Sociedad Argentina de Investigación Bioquímica y Biología Molecular.; 2008

Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular

LACTIC ACID PRODUCTION IN A ccpA MUTANT OF Lactobacillus casei Mariana C. Allievi, María Mercedes Palomino, Mariano Prado-Acosta, Carmen Sanchez Rivas and Sandra M. Ruzal Universidad de Buenos Aires. FCEyN. Dpto. de Química Biológica. Bs As. Argentina Lactic acid has applications in the pharmaceutical, chemical, textile and foods industries. It has received great attention as a precursor of the biodegradable polylactic acid. Great amounts of lactate are produced by Lactic Acid Bacteria, like Lactobacillus casei.  The catabolic repression can be an important limiting factor in the lactic acid synthesis. In an attempt to use industrial by-products like cheese whey, we evaluated the fermentative capacity of a mutant strain of the  catabolite repression regulator CcpA (BL71). We found that this strain is unrepressed for the nitrogen and carbohydrate metabolism. The proteolytic and peptidase activity were analyzed at the transcription and protein level. The transcription of the prtP gene was evaluated by Real Time PCR. The ccpA mutant showed to be derepressed.  Also milk-grown cultures of strain BL71 were quickly acidified, lowering the pH to one unit less than the wild type. The L-lactic acid production yield was also higher.  Different substrates and growing conditions for BL71 were analyzed in order to increase lactate production in low cost medium, like cheese whey. Our results indicated that the ccpA mutant is a good candidate for future developments in biotechnology.