Biopolymer production using fungus Mucor racemosus Fresenius and glycerol as substrate

Abstract

This study evaluated extracellular production of biopolymer using fungus Mucor racemosus Fresenius and glycerol as a carbon source. Initially employing conical flasks of 500 mL containing 100 mL of cultive medium with 0.18 ± 0.03 g.L^–1 of microorganisms, the results showed that the best conditions of the variables studied were: initial concentration of glycerol 50 g.L^–1, fermentation time of 96 h, inoculum cultivation time of 120 h, and aeration in two stages–the first 24 hours without aeration and 72 hours fermentation with aeration of 2 vvm and 2 g.L^–1 of yeast extract. The experiments conducted in a Biostat B fermenter with a 2.0 L capacity that contained 1.0 L of medium showed production of 16.35 g.L^–1 gum formed and 75% glycerol consumption. These conditions produced a biopolymer with the molecular weight and total sugar content of 4.607×10⁶ g.mol^–1 (Da) and 89.5%, respectively.

Keywords:
biopolymer; Mucor racemosus Fresenius; glycerol; aeration; fermentation; productivity