Pretreatments of Non-Woody Cellulosic Feedstocks for Bacterial Cellulose Synthesis

Abstract

Pretreatment of biomass is a key step in the production of valuable products, including high-tech bacterial cellulose. The efficiency of five different pretreatment methods of Miscanthus and oat hulls for enzymatic hydrolysis and subsequent synthesis of bacterial cellulose (BC) was evaluated herein: Hydrothermobaric treatment, single-stage treatments with dilute HNO3 or dilute NaOH solution, and two-stage combined treatment with dilute HNO3 and NaOH solutions in direct and reverse order. The performance of enzymatic hydrolysis of pretreatment products was found to increase by a factor of 4−7. All the resultant hydrolyzates were composed chiefly of glucose, as the xylose percentage in total reducing sugars (RS) was 1−9%. The test synthesis of BC demonstrated good quality of nutrient media prepared from all the enzymatic hydrolyzates, except the hydrothermobaric treatment hydrolyzate. For biosynthesis of BC, single-stage pretreatments with either dilute HNO3 or dilute NaOH are advised due their simplicity and the high performance of enzymatic hydrolysis of pretreatment products (RS yield 79.7−83.4%).

Miscanthus: A fast‐growing crop for environmental remediation and biofuel production

“…When pretreated with dilute sulfuric acid (H 2 SO 4 ), adding 0.08 mol/L MgO to the pretreatment liquid can neutralize the acetic acid produced during the reaction, reduce glycolysis, and eliminate the formation of inhibitors in downstream reactions (Liu et al, 2019). Kashcheyeva et al (2019) compared the enzymatic saccharification efficiency of Miscanthus biomass pretreated by five different pretreatment methods: hydrothermobaric treatment, single-stage treatments with dilute HNO 3 or dilute NaOH solution, and two-stage combined treatment with dilute HNO 3 and NaOH solutions in direct and reverse order. The results showed that except for the hydrothermal pretreatment, all other pretreatment methods can produce high-quality pretreated substrates.…”

“…Kashcheyeva et al. (2019) compared the enzymatic saccharification efficiency of Miscanthus biomass pretreated by five different pretreatment methods: hydrothermobaric treatment, single‐stage treatments with dilute HNO 3 or dilute NaOH solution, and two‐stage combined treatment with dilute HNO 3 and NaOH solutions in direct and reverse order. The results showed that except for the hydrothermal pretreatment, all other pretreatment methods can produce high‐quality pretreated substrates.…”

Recent advances in bacterial cellulose: a low-cost effective production media, optimization strategies and applications

“…The mixture was then autoclaved at 150 °C for 30 min, to yield 40-45% total sugars by using 7.2 g NaOH (Li et al 2021). Silver grass at 10 kg was pretreated by a 3-6 wt% NaOH solution at 90-95 °C for 6-8 h, to yield 85% reducing sugars (Kashcheyeva et al 2019). In NaOH pretreatment, the OH − targets the carbon of the ester linkage between lignin and hemicellulose, resulting in the irreversible hydrolysis of the ester bond and weakening the structural integrity of the lignocellulose (Modenbach and Nokes 2014).…”

Biorefining Oat Husks into High-Quality Lignin and Enzymatically Digestible Cellulose with Acid-Catalyzed Ethanol Organosolv Pretreatment

“…Oat straw and husks were investigated for the production of biogas [10], xylanase [11], xylitol [12], ethanol [12,13], bacterial cellulose [14][15][16], hydrogels [17], and polypropylene composites [18]. The pretreatment strategies to overcome lignocellulosic recalcitrance mostly included dilute-acid pretreatment using sulfuric acid [11,19] and nitric acid [13,[20][21][22][23], which exhibited the highest impact on dissolution of hemicellulose, and dilute-alkali pretreatment using sodium hydroxide [17,24] and ammonium hydroxide [25], which showed the highest impact on delignification.…”