Biosynthesis of multiple biopolymers by Sinorhizobium meliloti CFR 14 in high cell density cultures through fed batch fermentation

Shamala, T. R. and Rohinishree, Y. S. and Vijayendra, S. V. N. (2014) Biosynthesis of multiple biopolymers by Sinorhizobium meliloti CFR 14 in high cell density cultures through fed batch fermentation. Biocatalysis and Agricultural Biotechnology, 3. pp. 316-322.

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Abstract

Rhizobium spp. produce a variety of commercially important polymers during free living growth, which includes polyhydroxyalkanoate (PHA), exopolysaccharides (EPS), β-(1,2)-glucan, etc. Shake flask cultiva- tion of Sinorhizobium meliloti CFR 14 for 72 h with ammonium sulfate (0.318 g/L of N) and sucrose (12.64 g/L of C) resulted in 3.5 g/L of biomass with 1.7 g/L of PHA and 1.5 g/L of EPS. Corresponding yields enhanced to 5.0, 2.5 and 2 g/L, in a 48 h batch fermentation process at 30 1C, pH 7.0 and 40% air saturation level. Fed batch fermentation process with ammonium sulfate and sucrose as feed nutrients supported the production of 34.5 g/L of biomass with 17.2 g/L of PHA and 3.5 g/L of EPS. Concentration of glycogen, cellular and excreted β-(1,2)-glucan were about 0.3 g/L each under this condition. Fed batch process operated using ammonium hydroxide for dual purpose as a nitrogen source and for pH adjustment, lead to decreased biomass (29.6 g/L) and PHA yields (9.4 g/L). However, higher synthesis of EPS, glycogen, cellular and excreted β-(1,2)-glucan amounting to 9.0, 1.1, 1.3 and 2.0 g/L, respectively, were obtained indicating that the fermentation conditions like pH, dissolved oxygen level, amount of carbon and nitrogen play a significant role in the synthesis of intra- and extra-cellular polymers by the free living cells of S. meliloti.

Item Type:	Article
Uncontrolled Keywords:	Sinorhizobium meliloti, Polyhydroxyalkanoate, β-(12)-glucan, Exopolysaccharides, Glycogen, High cell density cultivation
Subjects:	500 Natural Sciences and Mathematics > 07 Life Sciences > 04 Microbiology > 02 Bacteriology 600 Technology > 05 Chemical engineering > 04 Fermentation Technology
Divisions:	Food Microbiology
Depositing User:	Somashekar K S
Date Deposited:	11 Mar 2025 08:35
Last Modified:	11 Mar 2025 08:35
URI:	http://ir.cftri.res.in/id/eprint/19267

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