Chemical Free Two-Step Hydrothermal Pretreatment to Improve Sugar Yields from Energy Cane

Ankita Juneja,Vijay Kumar Singh,Vijay Singh,Yadvika Yadvika,Deepak Kumar

doi:10.3390/en13215805

Abstract

Energy cane is an attractive lignocellulosic feedstock for processing into biofuels and bioproducts. A low-severity two-step hydrothermal pretreatment was investigated on energy cane for the production of monomeric sugar. Pretreatment temperature and time, in addition to the effect of disk milling, were observed for the glucose and xylose yields during hydrolysis. At residence times above 5 min in case of pretreatment at 200 °C, all of the hemicellulose was observed to be solubilized. The pretreatment condition of 200 °C for 10 min with disk milling was observed to provide the highest glucose concentration of 5.4%, and 200 °C for 5 min with disk milling provided the highest xylose concentration of 2.15%. The effect of disk milling in improving the sugar concentrations during hydrolysis was significant, especially at lower pretreatment temperatures and times. Low xylose yields at higher temperatures were attributed to the formation of degradation products at increased severity.

Highlights

Energy cane, unlike conventional sugarcane, is a non-food energy crop with high carbohydrate content, abundant availability, and low cost, making it attractive renewable feedstock for sugar production that can be converted to biofuel, biochemicals, and other bio-based products [1]
Xylans, extractives, acid soluble lignin (ASL), and acid insoluble lignin (AIL) were measured for raw biomass as well as for hot water pretreated biomass in nine conditions to observe the effect of pretreatment on energy cane composition (Table 1)
The raw biomass (on dry basis) contained about 55% carbohydrates, and the remaining components were extractives, acid insoluble lignin (AIL), and acid soluble lignin (ASL), which was in the range of previously reported compositions of energy cane [2,3]

Summary

Introduction

Unlike conventional sugarcane, is a non-food energy crop with high carbohydrate (fiber more than sucrose) content, abundant availability, and low cost, making it attractive renewable feedstock for sugar production that can be converted to biofuel, biochemicals, and other bio-based products [1]. Some recent studies have investigated various chemical pretreatment processes, including dilute acid [5], dilute ammonia [6,7,8], and ionic liquid [3,9], and have reported high sugar recoveries during hydrolysis. These processes suffer from several limitations, including sugar loss, inhibitor formation, and the need of corrosion resistant equipment and neutralization along with high cost of the pretreatment reagent.

Objectives

Methods

Results

Conclusion