Growth-associated and Non-growth-associated Bioethanol Production Kinetics from Nanoadsorbent-Detoxified Pretreated Hydrolysate

Abstract

Lignocellulosic-based (LCB) bioethanol production is challenged by the presence of inhibitory compounds in pretreated LCB hydrolysates limiting productivity. The negative impact of these inhibitory compounds on LCB bioethanol production kinetics remain understudied. Hence, this study modelled the kinetics of bioethanol fermentation using nanoadsorbent-detoxified potato peel waste (PPW) hydrolysate. Four different fermentation processes under both separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) conditions, including A (SHF with non-detoxified hydrolysate), B (SSF with non-detoxified hydrolysate), C (SHF with detoxified hydrolysate), and D (SSF with detoxified hydrolysate) were evaluated for bioethanol productivity. Higher productivity of 1.23 and 1.16-fold increments were recorded for fermentation processes C and D. Thereafter, the experimental data for cell growth, bioethanol production and substrate utilisation were well-fitted by the logistic function, modified Gompertz, and Luedeking-Piret models respectively. Moreover, the obtained root-mean-square error (RMSE) and mean square error (MSE) were low, while the accuracy factor (AF), bias factor (BF), slope and regression coefficient (R²) were close to 1. The bioethanol production processes were largely growth-associated (α) as α values (g ethanol/g substrate) were higher than β values (g ethanol/g substrate/h). The models were effectively implemented, demonstrating their usefulness to elucidate bioethanol productivity kinetics for improved process design and the development of large-scale bioethanol production.

Graphical Abstract