Growth and lactic acid production ofPediococcus pentosaceus at different gas environments,temperatures, pH values and nitrite concentrations |
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Authors: | Elisabeth Blickstad Göran Molin |
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Institution: | (1) Swedish Meat Research Institute, POB 504, S-24400 Kävlinge, Sweden |
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Abstract: | Summary In order to obtain a better understanding of the behaviour ofPediococcus pentosaceus in food products as well to facilitate the designing of industrial production processes for the organism, the growth and lactic acid production ofPediococcus pentosaceus in a complex glucose medium was followed in batch cultures at different gas environments (CO2, air, N2 and static cultures without gasflow), temperatures (10–50°C), pH (4.3–7.3) and nitrite concentrations (0–700 ppm). Optimal growth was obtained in CO2 at 40°C and pH 6.3 and resulted in a maximum specific growth rate (
max) of 1.27 h–1. In static culture at 40°C and pH 6.3 the
max was 1.21 h–1. The
max was, compared with static culture, reduced in air (12%) and nitrogen (26%). At 10°C the
max was reduced by 99% and at 50°C by 88%. The reduction at pH 4.3 and 7.3 was 65% and 57%, respectively. Nitrite did not affect the
max at any pH but increased the lag phase at pH 4.3 by a factor of 12. The lactic acid production was linked to the growth. The total amount of lactic acid produced was the same in all the tested gases and nitrite concentrations and also within the wide temperature range (15–45°C) and pH range (5.3–7.3). Mainly L(+)-lactic acid was produced during the exponential growth phase, but after this growth declined about 30% of the L(+)-lactic acid was converted to D(–)-lactic acid. The lactic acid product yield and the cellmass yied were both affected by the temperature but not by the pH. |
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