Influence of complex nutrients, temperature and pH on bacteriocin production by Lactobacillus sakei CCUG 42687.
The effects of process conditions and growth kinetics on the production of the bacteriocin sakacin P by Lactobacillus sakei CCUG 42687 have been studied in pH-controlled fermentations. The fermentations could be divided into phases based on the growth kinetics, phase one being a short period of exponential growth, and three subsequent ones being phases of with decreasing specific growth rate. Sakacin P production was maximal at 20 degrees C. At higher temperatures (25-30 degrees C) the production ceased at lower cell masses, when less glucose was consumed, resulting in much lower sakacin P concentrations. With similar media and pH, the maximum sakacin P concentration at 20 degrees C was seven times higher than that at 30 degrees C. The growth rate increased with increasing concentrations of yeast extract, and the maximum concentration and specific production rate of sakacin P increased concomitantly. Increasing tryptone concentrations also had a positive influence upon sakacin P production, though the effect was significantly lower than that of yeast extract. The maximum sakacin P concentration obtained in this study was 20.5 mg l(-1). On the basis of the growth and production kinetics, possible metabolic regulation of bacteriocin synthesis is discussed, e.g. the effects of availability of essential amino acids, other nutrients, and energy.
Aasen
I M
IM
SINTEF Applied Chemistry, Trondheim, Norway. inga.m.aasen@chem.sintef.no
Møretrø
T
T
Katla
T
T
Axelsson
L
L
Storrø
I
I
D000596:Amino Acids / Q000032:analysis; D001430:Bacteriocins / Q000096:biosynthesis*; D003470:Culture Media / Q000737:chemistry; D005285:Fermentation; D005947:Glucose / Q000032:analysis; D006133:Growth Substances / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000378:metabolism; D007778:Lactobacillus / Q000254:growth & development / Q000378:metabolism*; D013696:Temperature; D013997:Time Factors
D000596:Amino Acids; D001430:Bacteriocins; D003470:Culture Media; D006133:Growth Substances; C087217:sakacin P protein, Lactobacillus; D019344:Lactic Acid; D005947:Glucose