The production of biofuels from renewable energy sources is one of the most important issues in
biotechnology today. The process is known to generate various by-products, for example glycerol that is
obtained in the making of biodiesel from rapeseed oil. Crude glycerol may be utilized in many ways, including
microbial conversion to 1,3-propanediol. The main drawback of that technology is the use of high
concentrations of glycerol, which inhibits the growth of bacterial cells.
This study investigated the impact of crude glycerol on Clostridium butyricum
DSP1 and its ability to adapt
to an environment of high osmotic pressure. It was found that a crude glycerol concentration of up to 70 g/L did
not have an inhibitory effect on C. butyricum
DSP1. Adaptation procedures involving the passage of metabolically
active biomass from a fermentation medium with a lower concentration of crude glycerol to one with a greater
substrate concentration allowed breaking the barrier of high osmotic pressure (150 g/L crude glycerol) and
receiving a 1,3-PD concentration of 74 g/L in a batch culture operation. The work looked into intracellular
modifications shown by proteomic profiling in order to explain the mechanisms underlying the response and
adaptation of bacterial cells exposed to unfavorable environmental conditions.
This study of the effect of glycerol on the growth and metabolismof C. butyricum
that themaximum substrate concentrations that do not inhibit the metabolic activity of bacterial cells are 90 g/L
and 70 g/L for pure and crude glycerol, respectively.