Effects of diluents, temperature and pH on the enumeration and growth kinetics of Alicyclobacillus acidoterrestris in standard growth media.

Abstract This study reports the effects of dilutions in distilled water, 0.85% saline, 0.10% peptone water and phosphate-buffered saline on the viability of Alicyclobacillus acidoterrestris. Only peptone water caused a significant underestimation of viable populations of vegetative cells. Effects of temperature and pH on the growth kinetics of A. acidoterrestris in yeast starch glucose (YSG) media were characterized using a two-factored Central Composite Design (CCD). Response Surface Methodology was applied to quantify their influences on lag time, growth rate, and population change. Rates ranged from −0.37 (inactivating) to 1.07 (growth), while population change varied from −3.11 to 2.89 log. Values significantly fitted into a linear model for the growth rate response and a quadratic model for the population change response. pH was observed to be the significant factor affecting the response variables, having significant quadratic effects. Model validation with temperature and pH combinations unique from the CCD showed that predictions were within acceptable error margins for the population change model, while the growth rate model exhibited limited success rate. The results obtained in this study provide information on growth behaviors of A. acidoterrestris in standard media and can be further used in researches dealing with its maintenance and propagation. Highlights • Peptone water significantly underestimated viable vegetative cells. • Rates ranged from that of inactivation to growth. • Significant models for growth rate and population change were observed. • Only pH affected growth kinetic parameters significantly. • Model validation with unique temperature-pH combinations showed acceptable predictive efficacy for population change. [ABSTRACT FROM AUTHOR]