Role of Combined Na2HPO4 and ZnCl2 in the Unprecedented Catalysis of the Sequential Pretreatment of Sustainable Agricultural and Agro-Industrial Wastes in Boosting Bioethanol Production.

Shaimaa Elyamny,Ali Hamdy,Rehab Ali,Hesham Hamad

doi:10.3390/ijms23031777

Abstract

Improper lignocellulosic waste disposal causes severe environmental pollution and health damage. Corn Stover (CS), agricultural, and aseptic packaging, Tetra Pak (TP) cartons, agro-industrial, are two examples of sustainable wastes that are rich in carbohydrate materials and may be used to produce valuable by-products. In addition, attempts were made to enhance cellulose fractionation and improve enzymatic saccharification. In this regard, these two wastes were efficiently employed as substrates for bioethanol production. This research demonstrates the effect of disodium hydrogen phosphate (Na2HPO4) and zinc chloride (ZnCl2) (NZ) as a new catalyst on the development of the sequential pretreatment strategy in the noticeable enzymatic hydrolysis. Physico-chemical changes of the native and the pretreated sustainable wastes were evaluated by compositional analysis, scanning electron microscopy (SEM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). These investigations showed major structural changes after the optimized sequential pretreatment. This pretreatment not only influences the delignification process, but also affects the functionalization of cellulose chemical structure. NZ released a higher glucose concentration (328.8 and 996.8 mg/dl) than that of ZnCl2 (Z), which released 203.8 and 846.8 mg/dl from CS and TP, respectively. This work led to the production of about 500 mg/dl of ethanol, which is promising and a competitor to other studies. These findings contribute to increasing the versatility in the reuse of agricultural and agro-industrial wastes to promote interaction areas of pollution prevention, industrialization, and clean energy production, to attain the keys of sustainable development goals.

Highlights

IntroductionA growing developing populace and innovative advancements have led to an increment in solid wastes
Introduction distributed under the terms andShockingly, a growing developing populace and innovative advancements have led to an increment in solid wastes
Present in the plant cell wall to cover and protect the cellulose, obstructs the cellulose fractionation, and hinders the enzymatic hydrolysis that converts the cellulose to glucose, which leads to the production of bioeth

Summary

Introduction

A growing developing populace and innovative advancements have led to an increment in solid wastes. Agricultural wastes such as rice straw, wheat straw, and corn stover are attractive to be used as a lignocellulosic feedstock for biofuel production instead of traditional disposal by transportation to landfills, incineration, and composting [1]. Corn Stover (CS) is one of the lignocellulosic materials that have high productivity, local availability, and almost no cost. The global annual corn production is about 1 billion tons [2]. Two-thirds of the corn crop is a non-valuable which is considered as a solid waste that is so far over any local uses and leads to incorrect disposal problems. CS is always burnt in an open area and contributes to significant harmful effects on global warming, climate change, and human health as it leads to skin and eye irritation, neurological, cardiovascular, and respiratory diseases, such as lung infections, coughs, and bronchitis [3]

Objectives

Methods

Results