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Analysis of exponential growth data for yoghurt cultures
Author(s) -
Oner M. D.,
Erickson L. E.,
Yang S. S.
Publication year - 1986
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260280617
Subject(s) - exponential growth , exponential function , food science , biology , mathematics , biological system , mathematical analysis
Obtaining accurate estimates of maximum specific growth rate, growth yield, and product yield is important for many fermentation processes. A systematic procedure is presented to select the exponential growth region and estimate the maximum specific growth rate using the covariate adjustment method with all the available measured variables (i.e. biomass, substrate, and product). The procedure is applied to data collected during growth of pure and mixed cultures of Lactobacillus bulgaricus and Streptococcus thermophilus on 3% dry milk under anaerobic conditions. The estimation procedure gives good estimates with relatively narrow confidence intervals even though biomass concentration is measured by an indirect method. The estimated values of maximum specific growth rate range from 0.2805 h −1 for S. thermophilus (ATCC‐19258) to 0.4672 h −1 for S. thermophilus (Microlife). Growth and product yields are estimated using regression analysis and the data for the exponential growth region. The growth yields are compared to their theoretical maximum values.