Valorization of Corn Cobs for Xylitol and Bioethanol Production through Column Reactor Process

Abstract

Corncobs are a plentiful lignocellulosic material that can be utilized for energy production as well as the generation of other high-value products. Within the modern concept of biorefineries, we present processes conducted in a column reactor for the valorization of corncobs as a substrate for ethanol and xylitol production. In the first step, corncobs were subjected to acid hydrolysis, resulting in a hemicellulosic hydrolysate rich in xylose sugars intended for xylitol production by Candida tropicalis UFMGBX12-a. The YP/S (yield coefficient of product to substrate) and QP (productivity) values were approximately 0.2 g/g and 0.15 g/L·h, respectively, for the assays conducted in the column reactor. Next, the remaining solid portion of cellulignin was used for ethanol production through semi-simultaneous saccharification and fermentation process by Scheffersomyces parashehatae UFMG-HM 52.2. This approach involved an intensified successive process consisting of alkaline pretreatment of cellulignin, followed by enzymatic hydrolysis and fermentative processes conducted in the same reactor without biomass transfer. After obtaining the enzymatic hydrolysate, a QP value of 0.4 g/L·h for ethanol production was observed in the fermentation process conducted in the column reactor. The results demonstrate the potential of corncobs as a carbon source for biomolecules production, utilizing a process conducive to scale-up.

Pretreatment and enzymatic hydrolysis optimization of lignocellulosic biomass for ethanol, xylitol, and phenylacetylcarbinol co-production using Candida magnoliae

“…The corresponding values for CC, SCB, and RS were 694 ± 2.6 mg/g, 520 ± 1.6 mg/g, and 466 ± 4.2 mg/g, respectively. The appending of the alkaline pretreatment step could also be applied to remove the remaining lignin content after hemicellulose was solubilized in acid hydrolysate ( Tan et al, 2021 ; Antunes et al, 2023 ) which, in turn, resulted in the enhanced glucose conversion yield in the enzymatic hydrolysis step.…”