Enhanced production and in-situ removal of butanol during the fermentation of lignocellulosic hydrolysate of pineapple leaves

Abstract

The pineapple leaves waste was exploited as a potential biomass for butanol production. The cocktail of lignocellulolytic enzymes secreted by Sphingobacterium sp. ksn- 11 employed for the saccharification of steam pretreated pineapple leaves (100 g) which produced fermentable sugars (42.89 g) and polyphenols in the hydrolysate. The polyphenols were removed selectively by using residual cornhusk bed from the hydrolysate and subjected to fermentation by Clostridium acetobutylicum NCIM 2337. The butanol tolerance and production capacity of Clostridium acetobutylicum NCIM 2337 were enhanced by supplementing histidine and proline (0.5 %) to the fermentation medium by 1.8-fold and observed increase in butanol production (4.63 g/L). In order to minimize the sub-inhibitory effect of butanol, in-situ product recovery was carried out by the addition of Dowex L-493 resin which enhanced the butanol production (6.73 g/L) by 2.6-fold and achieved maximum yield of 0.16 g/g. Thus, the one pot step optimized process for butanol production was achieved.