Valorisation of fruit waste for enhanced exopolysaccharide production by Xanthomonas campestries using statistical optimisation of medium and process

The aim of this research work was to enhance the fermentative production of exopolysaccharide (EPS) with mixed fruit waste as a key substrate. Xanothomonas campestries was isolated from spoiled orange and its EPS production efficiency was determined using EPS medium. Prior to optimisation, the production was 3.4 g/L, upon optimizing the medium the production improved to 9.2 g/L. The medium formulation was studied by sequential addition of medium components and replacement of sugar with mixed fruit waste. In formulated medium, the production enhanced to 11.1 g/L. For further optimisation, the response surface methodology was used, which resulted in the enhancement of production to 14.5 g/L. The scale-up study was undertaken in a 10 L shake flask and fermenter. In 10 L flask EPS, production was 14.45 g/L in 100 h, whereas in 10 L fermenter it was 21.10 g/L in 60h only. The optimisation studies gave nearly 500% (6.2fold) enhanced EPS production and dwindle in fermentation time. Replacement of sucrose with fruit waste extract made the process environment friendly; omission of L-cystine and use of 50% reduced amount of sodium acetate in the medium lowered the production cost of EPS. The developed process resulted in the utilization of fruit waste and was also useful in solving the fruit waste disposal problem.

Automated summary

The aim of this research was to enhance the fermentative production of exopolysaccharide (EPS) using mixed fruit waste as a key substrate. By optimizing the medium formulation and utilizing response surface methodology, the production of EPS was significantly improved. The replacement of sucrose with fruit waste extract and the reduction in the use of specific components also reduced the production cost of EPS.