Simultaneous and comparative assessment of parent and mutant strain of Rhizobium meliloti for nutrient limitation and enhanced polyhydroxyalkanoate (PHA) production using optimization studies

Lakshman, Kshama and Rastogi, N. K. and Shamala, T. R. (2004) Simultaneous and comparative assessment of parent and mutant strain of Rhizobium meliloti for nutrient limitation and enhanced polyhydroxyalkanoate (PHA) production using optimization studies. Process Biochemistry, 39. pp. 1977-1983.

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Abstract

Nutrient limitation conditions, optimization and comparison of polyhydroxyalkanoate (PHA) yields and biomass production by parent and mutant strains of Rhizobium meliloti were investigated. Complex interactions among concentrations of sucrose (5–55 g/l), urea (0.05–0.65 g/l) inoculum (10–250 ml/l) and K2HPO4 (0.5–2 g/l), were studied using central composite rotatable design (CCRD) experiments. Phosphate-limiting medium (0.33 g K2HPO4/l) in the presence of excess carbon (sucrose 42.5 g/l) results in more production of PHA (2.2 g/l) in the parent strain. In comparison, the mutant strain required moderate levels of sucrose (30 g/l), along with excess of phosphate (1 g/l) for high PHA content of cell biomass (80%) and PHA yield (3.3 g/l). Optimised PHA production (biomass 4.8 g/l and PHA 3.09 g/l) by the parent strain occurred at: sucrose 51.58 g/l, urea 0.65 g/l, K2HPO4 0.48 g/l and inoculum 10 ml/l. In the mutant strain, higher yields of biomass (9.05 g/l) and PHA (5.66 g/l) were obtained in Optimised medium containing: sucrose 55 g/l, urea 0.65 g/l, K2HPO4 1.0 g/l and inoculum 150.58 ml/l.

Item Type:	Article
Uncontrolled Keywords:	Central composite rotatable design; Polyhydroxyalkanoate; Rhizobium meliloti; Response surface methodology; Mutant; Nutrient limitation
Subjects:	500 Natural Sciences and Mathematics > 07 Life Sciences > 04 Microbiology 600 Technology > 05 Chemical engineering > 08 Plastics Technology
Divisions:	Food Engineering Food Microbiology
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	04 Oct 2007 09:26
Last Modified:	30 Apr 2012 10:30
URI:	http://ir.cftri.res.in/id/eprint/1478

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