Optimization of alkaline pretreatment and enzymatic hydrolysis for the extraction of xylooligosaccharide from rice husk

This study explores the use of alkaline pretreatments to improve the hydrolyzation of rice husks to produce volatile fatty acids (VFAs). The study investigated the effects of reagent concentration and pretreatment time on protein, carbohydrates, and dissolved chemical oxygen demand (SCOD) dissolution after the pretreatment. The optimum alkaline pretreatment conditions were 0.30 g NaOH (g VS)−1, with a reaction time of 48 h. The experimental results show that when comparing the total VFA (TVFA) yields from the alkaline-pretreated risk husk with those from the untreated rice husk, over 14 d and 2 d, the maximum value reached 1237.7 and 716.0 mg·L−1 with acetic acid and propionic acid and with acetic acid and butyric acid, respectively. After the alkaline pretreatment, TVFAs increased by 72.9%; VFA accumulation grew over time. The study found that alkaline pretreatment can improve VFA yields from rice husks and transform butyric acid fermentation into propionic acid fermentation. The study results can provide guidelines to support the comprehensive utilization of rice husk and waste treatment.

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A Two-Step Ferric Chloride and Dilute Alkaline Pretreatment for Enhancing Enzymatic Hydrolysis and Fermentable Sugar Recovery from Miscanthus sinensis

Molecules ◽

10.3390/molecules25081843 ◽

2020 ◽

Vol 25 (8) ◽

pp. 1843

Author(s):

Lingci Li ◽

Peng Ye ◽

Mengyu Chen ◽

Shangyuan Tang ◽

Ying Luo ◽

...

Keyword(s):

Enzymatic Hydrolysis ◽

Ferric Chloride ◽

Morphological Changes ◽

Soluble Sugar ◽

Soluble Sugars ◽

Alkaline Pretreatment ◽

Miscanthus Sinensis ◽

Sugar Recovery ◽

Step Process ◽

Whole Process

A two-step process was proposed to enhance enzymatic hydrolysis of Miscanthus sinensis based on a comparative study of acid/alkaline pretreatments. Ferric chloride pretreatment (FP) effectively removed hemicellulose and recovered soluble sugars, but the enzymatic hydrolysis was not efficient. Dilute alkaline pretreatment (ALP) resulted in much better delignification and stronger morphological changes of the sample, making it more accessible to enzymes. While ALP obtained the highest sugar yield during enzymatic hydrolysis, the soluble sugar recovery from the pretreatment stage was still limited. Furthermore, a two-step ferric chloride and dilute alkaline pretreatment (F-ALP) has been successfully developed by effectively recovering soluble sugars in the first FP step and further removing lignin of the FP sample in the second ALP step to improve its enzymatic hydrolysis. As a result, the two-step process yielded the highest total sugar recovery (418.8 mg/g raw stalk) through the whole process.

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Bioconversion of coconut husk fibre through biorefinery process of alkaline pretreatment and enzymatic hydrolysis

Biomass Conversion and Biorefinery ◽

10.1007/s13399-020-00895-8 ◽

2020 ◽

Author(s):

Nur Akmal Solehah Din ◽

Seng Joe Lim ◽

Mohamad Yusof Maskat ◽

Nurul Aqilah Mohd Zaini

Keyword(s):

Enzymatic Hydrolysis ◽

Alkaline Pretreatment ◽

Coconut Husk

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Optimization and kinetic study of biogas production from rice husk through solid-state alkaline pretreatment method

Invertis Journal of Renewable Energy ◽

10.5958/2454-7611.2016.00024.2 ◽

2016 ◽

Vol 6 (4) ◽

pp. 175 ◽

Cited By ~ 1

Author(s):

Akinola David Olugbemide ◽

Labunmi Lajide ◽

Albert Adebayo ◽

Bodunde Joseph Owolabi

Keyword(s):

Solid State ◽

Kinetic Study ◽

Rice Husk ◽

Biogas Production ◽

Alkaline Pretreatment ◽

Pretreatment Method

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A Cation Study on Rice Husk Biomass Pretreatment with Aqueous Hydroxides: Cellulose Solubility Does Not Correlate with Improved Enzymatic Hydrolysis

ACS Sustainable Chemistry & Engineering ◽

10.1021/acssuschemeng.7b00647 ◽

2017 ◽

Vol 5 (6) ◽

pp. 5320-5329 ◽

Cited By ~ 6

Author(s):

Benjamin B. Y. Lau ◽

Tracey Yeung ◽

Robert J. Patterson ◽

Leigh Aldous

Keyword(s):

Enzymatic Hydrolysis ◽

Rice Husk ◽

Biomass Pretreatment

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Microwave-assisted Enzymatic Hydrolysis to Produce Xylooligosaccharides from Rice Husk Alkali- soluble Arabinoxylan

10.21203/rs.3.rs-690626/v1 ◽

2021 ◽

Author(s):

Wannaporn Klangpetch ◽

Alisa Pattarapisitporn ◽

Suphat Phongthai ◽

Pannapapol Jaichakan

Keyword(s):

Enzymatic Hydrolysis ◽

Sodium Hydroxide ◽

Microwave Heating ◽

Rice Husk ◽

Sugar Content ◽

Microwave Treatment ◽

Heating Process ◽

Microwave Pretreatment ◽

Microwave Assisted ◽

Pretreatment Time

Abstract This study aimed to produce xylooligosaccharide (XOS) and arabino-xylooligosaccharide (AXOS) from rice husk (RH) using microwave treatment combined with enzymatic hydrolysis and evaluate their prebiotic properties. The RH was pretreated by a microwave heating process at 140, 160 and 180°C for 5, 10, and 15 min to obtain crude arabinoxylan (AX). The results emphasized that increasing microwave pretreatment time increased sugar content. The crude AX was then extracted with 2% (w/v) sodium hydroxide at 25°C for 24 h. The obtained AX was then used as a substrate for XOS production by commercial xylanases. The results showed that the oligosaccharide produced by Pentopan Mono BG and Ultraflo Max provided xylobiose and xylotriose as the main products. Interestingly, AXOS was also present in the oligosaccharide product. Furthermore, the oligosaccharides obtained were able to promote the growth of Lactobacillus spp. and to resist degradation more than 70% after exposure to simulated human digestion.

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