RESPONSE SURFACE METHODOLOGY OPTIMIZATION OF BACTERIAL CELLULOSE PRODUCTION BY KOMAGATAEIBACTER HANSENII ATCC 53582 USING CARBON SOURCES BY TURMERIC HYDROLYSATE

Bacterial cellulose (BC) is a naturally occurring nanomaterial produced by fermentation some bacteria, such as those from the genus Komagataeibacter and may serve as an emulsifier and stabilizer for foods. Curcuma longa L. belongs to the family Zingiberaceae is commonly known as turmeric and their rhizomes have high starch content (more than 40%), which may be used as a source of carbohydrates for fermented products. This study aims to optimize the BC production synthesized by Komagataeibacter hansenii ATCC 53582 using as carbon source the sugars provide by enzymatic hydrolysis of turmeric (HT), with the purposes of maximizing yield. The fermentation was performed in the static culture at 30ºC for 10 days. Plackett-Burman design (PBD) was applied to screen the seven variables, which affect BC production and select the most significant ones. The factors tested were: (1) the effects of font’carbon sources (glucose commercial or from HT), (2) ethanol (0-1% v:v), (3) seed culture (1-6% v:v), (4) yeast extract (0.25-0.75 g.L-1), (5) peptone (0.25-0.75 g.L-1), (6) Na2HPO4 (0.09-0.27 g.L-1) and (7) citric acid (0.038-0.115 g.L-1). PBD results identified two significant factors (glucose and ethanol). Response Surface Methodology was used to evaluate the interactions of the significant parameters and to determine optimal conditions, 22 central composite rotational design (CCRD), with four axial points (α= ±1.41) and five central points for replications was used. The goodness of fit related to model was verified by regression analysis. The statistical data exhibited a significance of the regression and a determination coefficient (R2) of 0.7763, indicating that 77.63% of the variation in the response could be explained by the model, and the adjusted determination coefficient (R2 adjust = 0.5527). The optimal ethanol volume was 1.5% and 1.25g.L-1 for glucose. Statistical design contributed to assess BC production conditions, resulting in 5.45 g/L yield from HT.