Synthesis of Cellulose Nanocrystals (CNCs) from Brewer’s Spent Grain Using Acid Hydrolysis: Characterization and Optimization

Bisrat Yihun Matebie,S Venkatesa Prabhu,Aseel A Kadhem,Belachew Zegale Tizazu,Lakshmipathy R

doi:10.1155/2021/7133154

Bisrat Yihun Matebie, S Venkatesa Prabhu + Show 3 more

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https://doi.org/10.1155/2021/7133154

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Abstract

This study is aimed at utilizing brewery’s spent grain (BSG) byproduct for the synthesis of cellulose nanocrystals (CNCs) using acid hydrolysis and optimizing the hydrolysis parameters (hydrolysis time, temperature, liquid-solid ratio, and acid concentration). Alkali and bleaching treatment were done to remove hemicellulose and lignin from BSG. Optimization process was performed using central composite design (CCD) to obtain optimum value of cellulose nanocrystal (CNC) yield. The maximum cellulose nanocrystal (CNC) yield of 43.24% was obtained at optimum hydrolysis conditions of 50°C, 51 wt% acid concentration, 41 min, and liquid-solid ratio of 19 ml/g. The raw brewery spent grain; alkali-treated fiber, bleached fiber, and obtained CNC were characterized using scanning electron microscopy (SEM), XRD, particle analyzer, FTIR, and differential scanning calorimeter (DSC). The characterization results indicated that the obtained cellulose nanocrystal (CNC) has rod-like whisker shape with crystallinity of 76.3% and an average particle size of 309.4 nm.

Highlights

Cost minimization and environmental awareness issues become a common agenda for researchers [1]
Our study indicates a better yield was achieved with minimum time and acid concentration relative to cellulose nanocrystal (CNC) yield reported in the previous work
The hydrolysis parameters time, temperature, acid concentration, and liquid-solid ratio were investigated to obtain the optimum conditions for the production of cellulose nanocrystals from brewery spent grain

Summary

Introduction

Cost minimization and environmental awareness issues become a common agenda for researchers [1]. Developing a new green material from renewable biomass is one of a promising ways to solve cost and environmental pollution-related issues. Renewable biomasses commonly have three parts which are cellulose, lignin, and hemicellulose [2]. Cellulose is the most abundantly existing biopolymer which mainly exists in plant cell wall, and it found in animals such as tunicates, bacteria, sea mosses, and algae [3]. The estimated annual production of cellulose in the world is 1:5 × 1012 ton [1]. Even if cellulose is attractive due to its biodegradable, renewable, and nontoxic properties, it has a limitation towards its use in the area of various applications due to low strength, poor thermal stability, and high-water absorption properties [2]

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