Treating Distillers’ Grain from the Luzhou Aroma/Flavor Industry To Degrade Fiber

Abstract

To minimize environmental contamination and waste of resources, distillers' grain (DG) from the Chinese liquor industry was used to produce reducing sugars for Bacillus thuringiensis cultivation. Four different pretreatments, using sodium hydroxide (0.5−2% w/v, 50−121°C, 1 h), calcium hydroxide (0.2−4% w/v, 50−121°C, 1 h), dilute sulfuric acid (0.5−2% w/v, 50−121°C, 1 h), and hot water (50−121°C, 1 h), were investigated in order to determine the optimal method for degrading cellulose in DG to produce monomeric sugars. Enzymatic hydrolysis and fermentation followed each pretreatment method. The results showed that the highest yield of monomeric sugars was obtained by using 2% dilute sulfuric acid treatment at 121°C for 1 h (giving 313 g/kg DG), which was significantly higher (p < 0.001) than the yields obtained using other pretreatment methods. The highest spore count was achieved using this pretreatment with the addition of supplements. The utilization of DG in this study provides a plentiful carbon source that is effective not only for cultivating microorganisms but also for reducing industrial waste.

Pretreatment of wheat straw leads to structural changes and improved enzymatic hydrolysis

“…These high conversion rates could be attributed to the degradation of hemicellulose and lignin after pretreatment (Table 1 ). Hemicellulose and lignin negatively affects enzymatic hydrolysis by binding to cellulose, thereby impeding its access to cellulose 41 , 42 . The degradation of hemicellulose and lignin could increase the pore size and accessible surface of the biomass, which in turn enhances accessibility to cellulose, thereby increasing cellulose conversion rate 42 , 43 .…”

“…Three different pretreatments were tested in this study, including sulfuric acid pretreatment (0.5–4% w/v, 50–121 °C, 1 h), sodium hydroxide pretreatment (0.5–4% w/v, 50–121 °C, 1 h), and hot water pretreatment (50–175 °C, 1 h). The pretreatment was performed according to a previous study 41 . Briefly, 5 g of WS was placed in 50 mL of pretreatment liquid and sealed in an Erlenmeyer flask in an autoclave and then heated at different temperatures for 1 h (Table 2 ).…”

Utilization of nematode-infected pinewood for mushroom cultivation and production of reducing sugar

“…However, the percentage of lignin content in the healthy pine substrate (37.2%) was higher than that of healthy pine sawdust (34.1%) due to the partial digestion of the polysaccharide content during the cultivation of F. velutipes, which indirectly increased the proportion of lignin content in the material. In addition, the percentage of polysaccharide content in the four kinds of materials (54.2%, 51.4%, 48.4%, and 50.2%) was higher than that of the common agricultural wastes such as corn straw (37.7%) (Chen et al 2016) and distiller's grains (41.6%) (Zheng et al 2015). Therefore, all four materials might have great potential to produce reducing sugar.…”

“…As shown in Table 3, the alkali-treated reducing sugar content was not detectable. The reason may be that sodium hydroxide reacts chemically with the monosaccharides hydrolyzed by cellulose, resulting in a decrease in the yield of reducing sugars under high-temperature conditions (Zheng et al 2015). The yield of reducing sugar after hot water treatment was also unsatisfactory.…”

“…The results show that the nematode-infected pine substrate still has a great utilization value due to its capacity to be recycled to produce reducing sugar. Moreover, the obtained reducing sugar can be used as a cost-effective carbon source for cultivating microorganisms being of great benefit not only for the biopesticide manufacture but also for reducing agricultural waste (Wu et al 2013;Zheng et al 2015Zheng et al , 2018.…”