Pretreatment of Cellulosic Waste Sawdust Into Reducing Sugars Using Mercerization and Etherification

Abstract

Pretreatment of sawdust using a combination of sodium hydroxide (NaOH) and monochloroacetic acid (MCA) was investigated for the formation of reducing sugars. Optimum conditions for the pretreatment process were determined by the amount of reducing sugars formed during the enzymatic hydrolysis of the pretreated substrate. It was found that mercerization by NaOH played an important role in increasing the degree of substitution (DS) and that the maximum solubility was achieved during the etherification by MCA. A maximum amount of 34.2% lignin was removed in the process. As the DS of the substrate was increased, the efficiency of the hydrolysis process increased, leading to the higher yield of reducing sugars. The optimum operating conditions for the pretreatment process were determined to be 75 o C at 90 rpm for 4 hours (2 hours for mercerization plus 2 hours for etherification). Under these operating conditions, with 1% (w/v) NaOH and 2% (w/w) MCA loading, a maximum DS of 0.2 and a solubility of 10.3% was attained. At 75 o C and after 48 hours of the hydrolysis process, cellulases from Aspergillus niger resulted in the production of 2.88 g/L of glucose with a yield of 62.72% reducing sugars. X-ray diffraction (XRD) revealed reduced crystallinity of the sawdust and Scanning Electron Microscopy (SEM) showed distortion of the structure after pretreatment.

Effect of silica and lignocellulosic additives on the formation and the distribution of meso and macropores in foam metakaolin-based geopolymer filters for dyes and wastewater filtration

“…This could be due to the deacetylation of sawdust in alkali media [46][47][48] resulting in formation organic salts [47,49]. For example, Of et al [50] suggested cellulosate is an intermediate compound formed from cellulose in alkali medium through carboxymethyl process at low temperature at 70 °C. In the given work the oven curing at 70 °C, the appearance of the band near 895 cm −1 (Fig.…”

Isolasi dan Karakterisasi Enzim Selulase dari Keong Sawah Pila ampullaceal Menggunakan Substrat Serbuk Gergaji Kayu

“…Serbuk gergaji kayu merupakan bahan lignoselulosa yang memiliki kandungan selulosa dan lignin yang besar. Untuk meningkatkan proses hidrolisis secara enzimatik maka perlu dilakukan perlakuan awal yang disebut proses delignifikasi dengan menggunakan bantuan senyawa katalis, salah satu caranya adalah dengan menggunakan katalis kimia berupa senyawa NaOH [21,22]. Berdasarkan Tabel 1, serbuk gergaji yang telah melalui proses delignifikasi dengan NaOH memiliki kadar selulosa yang lebih tinggi.…”

Synthesis of gamma irradiated acrylic acid-grafted-sawdust (SD-g-AAc) for trivalent chromium adsorption from aqueous solution

“…Saw dust is a polycrystalline structure materials, which contain crystalline cellulose and amorphous lignin region ( Kim et al 2012 ). The XRD pattern of t-SD-g-AAc is shown in the Fig.…”