초록
<P><B>Abstract</B></P> <P>Calcium carbonate was evaluated as a replacement for the base during the fermentation of glycerol by a highly productive strain of 1,3-propanediol (PDO), viz., <I>Clostridium butyricum</I> JKT37. Due to its high specific growth rate (µ<SUB>max</SUB> =0.53h<SUP>−1</SUP>), 40g/L of glycerol was completely converted into 19.6g/L of PDO in merely 7h of batch fermentation, leaving only acetate and butyrate as the by-products. The accumulation of these volatile fatty acids was circumvented with the addition of calcium carbonate as the pH neutraliser before the fermentation was inoculated. An optimal amount of 15g/L of calcium carbonate was statistically determined from screening with various glycerol concentrations (20–120g/L). By substituting potassium hydroxide with calcium carbonate as the pH neutraliser for fermentation in a bioreactor, a similar yield (Y<SUB>PDO/glycerol</SUB> =0.6mol/mol) with a constant pH was achieved at the end of the fermentation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel strain for PDO production was isolated from palm oil mill effluent. </LI> <LI> Batch productivity in bioreactor can achieve as high as 2.80g/Lh. </LI> <LI> Proposed the use of calcium carbonate to maintain pH range during fermentation. </LI> <LI> A control fermentation volume was established without the addition of acid or base. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>