Effect of Glycerol Pretreatment on Levoglucosan Production from Corncobs by Fast Pyrolysis.

Liqun Jiang,Zengli Zhao,Fang He,Xiaobo Wang,Anqing Zheng,Nannan Wu,Xinjun Feng,Haibin Li,Ming Liu

doi:10.3390/polym9110599

Abstract

In this manuscript, glycerol was used in corncobs’ pretreatment to promote levoglucosan production by fast pyrolysis first and then was further utilized as raw material for chemicals production by microbial fermentation. The effects of glycerol pretreatment temperatures (220–240 °C), time (0.5–3 h) and solid-to-liquid ratios (5–20%) were investigated. Due to the accumulation of crystalline cellulose and the removal of minerals, the levoglucosan yield was as high as 35.8% from corncobs pretreated by glycerol at 240 for 3 h with a 5% solid-to-liquid ratio, which was obviously higher than that of the control (2.2%). After glycerol pretreatment, the fermentability of the recovered glycerol remaining in the liquid stream from glycerol pretreatment was evaluated by Klebsiella pneumoniae. The results showed that the recovered glycerol had no inhibitory effect on the growth and metabolism of the microbe, which was a promising substrate for fermentation. The value-added applications of glycerol could reduce the cost of biomass pretreatment. Correspondingly, this manuscript offers a green, sustainable, efficient and economic strategy for an integrated biorefinery process.

Highlights

Growing global environmental concerns and the continuous depletion of fossil fuels lead to the search for sustainable alternative energy resources and technologies
The pretreated corncobs were fast pyrolyzed for levoglucosan production, while the liquid fraction from glycerol pretreatment was collected to evaluate its fermentability
Glycerol was utilized in corncobs’ pretreatment prior to fast pyrolysis for levoglucosan production, and the recovered glycerol was further utilized for microbial fermentation to evaluate its fermentability

Summary

Introduction

Growing global environmental concerns and the continuous depletion of fossil fuels lead to the search for sustainable alternative energy resources and technologies. Lignocellulose is the most plentiful form of biomass and the most abundant polysaccharide on Earth, which has already attracted unprecedented concern [1]. There is a widespread interest in using sugars derived from lignocellulose to produce biofuels and chemicals. Fast pyrolysis is a little-explored alternative thermo-chemical depolymerization route to release sugars, which presents an excellent opportunity to establish a biorefinery [3]. Levoglucosan is the main product from cellulose fast pyrolysis, and the yield reaches as high as 59%. Levoglucosan is of great value and is mainly utilized as a chiral raw material to synthesize stereoregular polysaccharides and chiral chemicals [4,5]. Due to the presence of levoglucosan kinase, Aspergillus terreus, Aspergillus niger CBX-209, oleaginous yeasts

Methods

Results

Conclusion