Selection of optimal conditions for anti-corrosive microbial biopolymer production by the Flavobacterium strain using response surface methodology (RSM)

Various methods have been proposed to deal with corrosion. One of these methods is using of paints and coatings. In formulation of paints and coatings several anti-corrosion compounds are applied that slow down the corrosion process. In this respect, using microbial biopolymers can improve this problem in the industry with lower costs because of biopolymer production not required to factory and advanced industry. in this study, the effects of temperature, pH and agitation on the biopolymer production using response surface methodology (RSM) were evaluated.
To produce biopolymer, the culture medium (300 ml) were added in the 500 ml erlenmeyer flasks. Then, the bacterial preculture medium (6% V/V) were inoculated in the flasks and incubated for 96hr in different conditions (agitation speed, tempreture and pH). Afterwards, the medium was centrifuged at 9000 rpm for 10 min and the supernatant was mixed with triple volume of chilled absolute ethanol and stored at 4°C for 24hr to precipitate.
Analysis of the results of design experiments indicate that the biopolymer production­ was strongly governed by the temperature, pH and agitation. The biopolymer production increased steadily up to pH 8 and decreased in the higher pH values. Also, for cell growth suitable temperature was 33°C and maximum concentration of the biopolymer production was agitation of 210 rpm. Finally, maximum concentration of the biopolymer production (14.3g/l) was determined to be in pH of 8, temperature of 33°C and agitation of 210­rpm.
Discussion and Anti-corrosive biopolymer production by Flavobacterium sp. affected significantly by physical parameters. The results of the biopolymer production by investigating the conditions of temperature, pH and agitation after optimization, indicates the importance of this parameter for economic production of biopolymer.