Use of corncob and pineapple peel as associated substrates for biosurfactant production

Abstract

Biosurfactants are amphiphilic biomolecules with promising tensoative and emulsifying properties that find application in the most varied industrial sectors: environment, food, agriculture, petroleum, cosmetics, and hygiene. In the current work, a 2³ full-factorial design was performed to evaluate the effect and interactions of pineapple peel and corncob as substrates for biosurfactant production by Bacillus subtilis LMA-ICF-PC 001. In a previous stage, an alkaline pretreatment was applied to corncob samples to extract the xylose-rich hydrolysate. The results indicated that pineapple peel extract and xylose-rich hydrolysate acted as partial glucose substitutes, minimizing production costs with exogenous substrates. Biosurfactant I (obtained at 8.11% pineapple peel extract, 8.11% xylose-rich hydrolysate from corncob, and 2.8109 g/L glucose) exhibited a significant surface tension reduction (52.37%) and a promising bioremediation potential (87.36%). On the other hand, biosurfactant III (obtained at 8.11% pineapple peel extract, 31.89% xylose-rich hydrolysate from corncob, and 2.8109 g/L glucose) exhibited the maximum emulsification index in engine oil (69.60%), the lowest critical micellar concentration (68 mg/L), and the highest biosurfactant production (5.59 g/L). These findings demonstrated that using pineapple peel extract and xylose-rich hydrolysate from corncob effectively supports biosurfactant synthesis by B. subtilis, reinforcing how agro-industrial wastes can substitute traditional carbon sources, contributing to cost reduction and environmental sustainability.

Keywords: Ananas comosus; Bacillus subtilis; Zea mays; Agro-industrial waste; Bioremediation potential; Emulsification index; Surface tension.