초록
<P><B>Abstract</B></P> <P>Lactic acid (LA) fermentation performances and characteristics of <I>Streptococcus thermophilus</I> YI-B1 and <I>Lactobacillus casei</I> Shirota were evaluated by the development of unstructured models including both substrate and product inhibitions on semi-defined medium. Cell growth was ceased at 300gL<SUP>−1</SUP> of glucose, 320gL<SUP>−1</SUP> of fructose and 101.1gL<SUP>−1</SUP> of LA for <I>L. casei</I> Shirota, while in the case of <I>S. thermophilus</I> YI-B1 they were 180gL<SUP>−1</SUP> for glucose and 49.9gL<SUP>−1</SUP> for LA. An unstructured modified Monod expression was used to predict the fermentation process. The obtained R<SUP>2</SUP> values for the fitted models were 0.95 for <I>L. casei</I> Shirota and 0.80 for <I>S. thermophilus</I> YI-B1. Since <I>L. casei</I> Shirota was more tolerant than <I>S. thermophilus</I> YI-B1, it was chosen for further examination in a laboratory-scale bioreactor. With the re-optimisation of a few model parameters, the unstructured models had shown a good agreement between experimental data and model simulations by using both semi-defined medium and complex media derived from food waste. Future work could further expand this dynamic model to predict fed-batch fermentation and investigate the fermentation characteristics using other carbon sources.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Lactic acid fermentation performance were evaluated by developing unstructured models. </LI> <LI> Inhibitory effects of glucose, fructose and lactic acid were studied in shake flasks. </LI> <LI> The obtained R<SUP>2</SUP> values were 0.95 for <I>L. casei</I> Shirota and 0.80 for <I>S. thermophilus</I>. </LI> <LI> A good agreement between experimental data and model simulations in 2L bioreactor. </LI> <LI> The models were also successfully applied to complex media derived from food waste. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>