Application of Experimental Design Method for the Optimisation of Xanthan Gum Production from Pineapple Peels Using Xanthomonas Campestris via Submerged Fermentation

Abstract

Xanthan gum is a major biopolymer which finds a lot of applications industrially and domestically. Biotechnological production of xanthan gum from waste biomass has been reported to be sustainable in terms of economics and viability. In this study, xanthan gum was produced from pineapple peels using Xanthomonas campestris by submerged fermentation. A three-variable, three-level Box-Behnken design (BBD) was used to develop a statistical model to study the effects of fermentation time, concentration of nitrogen (NH 4 NO 3 ) and phosphorus (KH 2 PO 4 ) on the amount of xanthan gum produced. Response surface methodology (RSM) was used to optimise these process variables. Results obtained showed that the model was statistically significant (p<0.0001) and did not show lack of fit (R 2 =0.989). The results also showed that xanthan gum production was positively influenced by high levels of phosphorus and low levels of nitrogen. Increasing the fermentation time also favoured the production of xanthan gum. Results obtained from RSM revealed that the optimum fermentation time, nitrogen and phosphorus concentration were 3 days, 2 g/L and 15 g/L respectively. Under these conditions, the xanthan concentration was obtained as 8.48 g/L. Validation of the model indicated no significant difference between predicted and experimental values. http://dx.doi.org/10.4314/njt.v34i3.10