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The process of ethanol production from distilled grain waste based on concentrated H 2 SO 4 saccharification
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Distilled grain waste eluted from Chinese spirit making is rich in carbohydrates, and could potentially serve as feedstock for the production of bio-fuel ethanol. Our study evaluated two types of saccharification methods that convert distilled grain waste to monosaccharides: enzymatic saccharification and concentrated H2SO4 saccharification. Result...
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Citations
... Furthermore, other compounds extracted from cereal husk have multifold uses of which the major is bio-ethanol production (Wu et al., 2018). Rice and lentil husk is another important renewable waste that displays profound application in the process of fermentation sustainably which aids in regulating porosity which aids in optimum gaseous interchange rate during the process of distillation (Tan et al., 2014). ...
... 2 However, due to its unsuitable protein and fiber contents, DGW has low economic benefit as animal feed, and most DGW traditionally end up in landfills, bringing up serious environmental concerns. 4 Recently, more stringent regulations and diminishing land availability have resulted in the increasingly difficult and costly landfill for DGW to be constructed and operated. ...
... starch (based on dry weight), 4,5 which can be facilely hydrolyzed into fermentable sugar without harsh and costly pretreatment. Therefore, DGW has served as an excellent feedstock for the production of biochemicals and energy substances, such as ethanol, 4 surfactin, 5 2,3-butanediol, 6 succinic acid 7 and bacterial cellulose. 8 In recent years, butanol has become increasingly interesting as an important chemical intermediate for the precursors of the plastics, pharmaceutical and energy industries. ...
Background
Distillers' grain waste (DGW) is the main by‐product in the Baijiu‐making process and its management remains a great challenge for the Baijiu industry. To address this issue, an integrated biobutanol and biomethane production process was established to obtain valuable products from DGW and reduce environmental pollution.
Results
In the integrated process, DGW was hydrolyzed and detoxified to produce biobutanol, while the distillery waste derived from solvent extraction process was used for biomethane fermentation. After the optimization of overliming detoxification of DGW hydrolysate by artificial neural network and genetic algorithm, totals of 10.65 ± 0.07 g L⁻¹ butanol and 4.51 ± 0.21 g L⁻¹ isopropanol were attained with negligible amounts of acetone and ethanol (i.e. 0.14 ± 0.00 and 0.52 ± 0.06 g L⁻¹, respectively). Anaerobic digestion of the distillery waste was efficient, and the chemical oxygen demand removal rate approached 92.3 ± 0.1% with a methane yield of 167.8 ± 1.2 mL g⁻¹ TCODremoved. Moreover, the anaerobic digestion effluent could be recycled as a potential substitute for process water in biobutanol fermentation without having any negative effect on enzymatic hydrolysis of DGW, and the butanol production also reached 8.19 ± 0.29 g L⁻¹.
Conclusion
The present study provides a new idea for comprehensive utilization of DGW towards energy and resource recovery, without secondary pollution. © 2023 Society of Chemical Industry.
... Among them, cellulose and hemicellulose can be converted into glucose after hydrolysis. Xylose and other fermentable sugars (monosaccharides) can be further used to produce biofuels (Tan et al., 2014;Taha et al., 2016). ...
Traditional Chinese medicine is one of the ancient medicines which is popular in Asian countries, among which the residue produced by the use of anti-biodegradables is endless, and causes significant adverse impacts on the environment. However, the high acidity of anti-biodegradable residues and some special biological activities make it difficult for microorganisms to survive, resulting in a very low degradation rate of lignocellulose in naturally stacked residues, which directly impedes the degradation of residues. We aimed to identify the fungal strains that efficiently biodegrade anti-biodegradable residue and see the possibility to improve the biodegradation of it and other agricultural wastes by co-cultivating these fungi. We isolated 302 fungal strains from anti-biodegradable residue to test hydrolysis ability. Finally, we found Coniochaeta sp., Fomitopsis sp., Nemania sp., Talaromyces sp., Phaeophlebiopsis sp. which inhabit the anti-biodegradable residues are capable of producing higher concentrations of extracellular enzymes. Synergistic fungal combinations (viz., Fomitopsis sp. + Phaeophlebiopsis sp.; Talaromyces sp. + Coniochaeta sp. + Fomitopsis sp.; Talaromyces sp. + Fomitopsis sp. + Piloderma sp. and Talaromyces sp. + Nemania sp. + Piloderma sp.) have better overall degradation effect on lignocellulose. Therefore, these fungi and their combinations have strong potential to be further developed for bioremediation and biological enzyme industrial production.
... Distilled grain waste (DGW), the primary by-product of the Chinese spirit-making process, is produced and discharged as the primary solid waste [5,6]. Approximately 25 million tons of DGW have been generated annually in China in the past 5 years. ...
Background
Pleurotus ostreatus is an edible mushroom popularly cultivated worldwide. Distilled grain waste (DGW) is a potential substrate for P. ostreatus cultivation. However, components in DGW restrict P. ostreatus mycelial growth. Therefore, a cost-effective approach to facilitate rapid P. ostreatus colonization on DGW substrate will benefit P. ostreatus cultivation and DGW recycling.
Results
Five dominant indigenous bacteria, Sphingobacterium sp. X1, Ureibacillus sp. X2, Pseudoxanthomonas sp. X3, Geobacillus sp. X4, and Aeribacillus sp. X5, were isolated from DGW and selected to develop a consortium-based microbial agent to compost DGW for P. ostreatus cultivation. Microbial agent inoculation led to faster carbohydrate metabolism, a higher temperature (73.2 vs. 71.2 °C), a longer thermophilic phase (5 vs. 3 days), and significant dynamic changes in microbial community composition and diversity in composts than those of the controls. Metagenomic analysis showed the enhanced microbial metabolisms, such as xenobiotic biodegradation and metabolism and terpenoid and polyketide metabolism, during the mesophilic phase after microbial agent inoculation, which may facilitate the fungal colonization on the substrate. In accordance with the bioinformatic analysis, a faster colonization of P. ostreatus was observed in the composts with microbial inoculation than in control after composting for 48 h, as indicated from substantially higher fungal ergosterol content, faster lignocellulose degradation, and higher lignocellulase activities in the former than in the latter. The final mushroom yield shared no significant difference between composts with microbial inoculation and control, with 0.67 ± 0.05 and 0.60 ± 0.04 kg fresh mushroom/kg DGW, respectively ( p > 0.05).
Conclusion
The consortium-based microbial agent comprised indigenous microorganisms showing application potential in composting DGW for providing substrate for P. ostreatus cultivation and will provide an alternative to facilitate DGW recycling.
... Distilled grain waste (DGW) is the main solid waste generated in the Chinese spirit industry and its annual production is estimated to be over 100 million tons [1]. Traditionally, DGW is incinerated to produce steam; however, due to the high moisture in DGW, incineration has high costs and energy consumption [2,3]. Therefore, an effective method to deal with DGW is urgently needed for the Chinese spirit industry. ...
... It revealed a gradual increase in the richness and diversity of bacterial communities in the composting of DGW. The process of brewing Chinese spirit is usually in an open pit through solid-state fermentation; both ethanol fermentation and lactic acid fermentation occur [2,3]. The higher ethanol and VFAs concentrations probably suppressed the activity of most microbes, thus, a lower richness and diversity of bacteria in raw DGW were readily comprehensible. ...
Distilled grain waste (DGW) can be converted to organic fertilizer via aerobic composting process without inoculating exogenous microorganisms. To illustrate the material conversion mechanism, this study investigated the dynamic changes of bacterial community structure and metabolic function involved in DGW composting. Results showed that a significant increase in microbial community alpha diversity was observed during DGW composting. Moreover, unique community structures occurred at each composting stage. The dominant phyla were Firmicutes, Proteobacteria, Actinobacteriota, Bacteroidota, Myxococcota, and Chloroflexi, whose abundance varied according to different composting stages. Keystone microbes can be selected as biomarkers for each stage, and Microbispora, Chryseolinea, Steroidobacter, Truepera, and Luteimonas indicating compost maturity. Co-occurrence network analysis revealed a significant relationship between keystone microbes and environmental factors. The carbohydrate and amino acid metabolism were confirmed as the primary metabolic pathways by metabolic function profiles. Furthermore, nitrogen metabolism pathway analysis indicated that denitrification and NH3 volatilization induced higher nitrogen loss during DGW composting. This study can provide new understanding of the microbiota for organic matter and nitrogen conversion in the composting process of DGW.
... Traditionally, DGW has been used as an animal feed because of its high nutrient components. However, the required protein and fiber contents in animal feed are difficult to achieve and considerable amounts of DGW are still ended up as industrial wastes for landfill without prior treatment, resulting in the serious environmental risks [14,15]. In recent years DGW has been studied as feedstock for the production of valuable products, due to its high unused starch, protein, water-soluble vitamin, and mineral content. ...
... The high content of fiber was attributed to large amounts of the husk of fermentative materials and part of rice husk remained in DGW. Rice husk was commonly supplemented before Baijiu fermentation to keep the fermentative materials loose, and before distillation to increase the steam permeability [15]. Lipid and ash contents in DGW were 5.8-12.6% ...
A new aerotolerant strain of Clostridium beijerinckii LY-5 was isolated from the pit mud of the Chinese Baijiu-making process for butanol production. Plackett–Burman design and artificial neural network were used to optimize the fermentation medium and a total of 13.54 ± 0.22 g/L butanol and 19.91 ± 0.52 g/L ABE were attained under aerotolerant condition. Moreover, distillers’ grain waste (DGW), the main by-product in the Baijiu production process, was utilized as potential substrate for butanol production. DGW was hydrolyzed by α-amylase and glucoamylase and then fermented after a detoxifying process of overliming. Butanol and ABE concentrations were 9.02 ± 0.18 and 9.57 ± 0.19 g/L with the yield of 0.21 and 0.23 g/g sugar, respectively. The higher ratio of butanol to ABE might be caused by the inhibitors in DGW medium affecting the metabolic pathways of C. beijerinckii LY-5 and approximately 1.48 ± 0.04 g/L isopropanol was found at the end of fermentation. This work highlights the feasibility of using DGW as a promising feedstock for butanol production by a new aerotolerant strain of C. beijerinckii LY-5, with benefit to the environment.
Graphic abstract
... The byproduct of barley pearling process serves as a rich source of bioactive compounds like phytates, insoluble dietary fiber, phenolics and it contains 2.7 times more vitamin E than in whole barley grain (Papageorgiou and Skendi, 2018). Rice husk is used in fermentation process to adjust moisture, maintain the porosity of fermentative material for gaseous exchange during distillation (Tan et al., 2014). ...
With the changing life-style and rapid urbanization of global population, there is increased generation of food waste from various industrial, agricultural, and household sources. According to Food and Agriculture Organization (FAO), almost one-third of the total food produced annually is wasted. This poses serious concern as not only there is loss of rich resources; their disposal in environment causes concern too. Food waste is rich in organic, thus traditional approaches of land-filling and incineration could cause severe environmental and human health hazard by generating toxic gases. Thus, employing biological methods for the treatment of such waste offers a sustainable way for valorization. This review comprehensively discusses state-of-art knowledge about various sources of food waste generation, their utilization, and valorization by exploiting microorganisms. The use of microorganisms either aerobically or anaerobically could be a sustainable and eco-friendly solution for food waste management by generating biofuels, electrical energy, biosurfactants, bioplastics, biofertilizers, etc.
... The establishment of scenarios are referred from various previously studies. Cesaro and Belgiorno, (2015); Miezah et al. (2017) and Tan et al. (2014) made an effort to produce biogas as well as bioethanol from Hao et al. (2015); Li et al. (2016) and Wen et al. (2016) provided examples of converting FW into biogas and biodiesel. Karmee and Lin, (2014), Zhang et al. (2016) and Sawatdeenarunat et al. (2016) also explained ways to convert FW into various biofuels. ...
Consistent material and substance flow diagrams for five alternative biorefinery scenarios for treating Chinese food waste were obtained by combining reported experimental research data and material flow analysis. The biorefinery alternatives produced biogas, biomethane, bioethanol and biodiesel in various combinations. The compiled statistical data compiled showed that 100 t of Chinese food waste could produce 16 ± 1.1 t of biogas as a single technology and that other advanced biorefinery concepts could produce 5 ± 0.4 t of biomethane, 4 ± 1.6 t of bioethanol and/or 3 ± 0.2 t of biodiesel. In terms of substance flow, biorefinery scenarios transfer up to 75% of the total initial carbon in the food waste into bioproducts, while 22% of carbon is emitted, primarily as carbon dioxide. The compost obtained by composting the dewatered digestate contained about 75% of input P, 27% of input K and 6% of input N. About 15% of input N was lost to the air during composting. The remaining C, N, P and K were in the wastewater. Introducing biorefinery concepts to the management of Chinese food waste can facilitate the generation of high-value bioproducts. However, biorefinery concepts are technologically complicated and the energy consumption may triple relative to that of only biogas production. The issue of a considerably large liquid fraction in all cases still needs to be addressed. The material flow diagrams in this work constitute a consistent platform for assessing future scenarios for treating Chinese food waste from a technical, economical as well environmental perspective.
... Approximately 25 million tons of distilled grain waste (DGW), the main by-product of the Chinese liquor producing process, is generated every year [1]. This waste is discharged during the distillation process and consists of fermented grains, such as sorghum, corn, wheat, and rice, along with rice husk [2]. Owing to its high content of organic matter, at 80% on a dry basis, the significant quantity of DGW poses serious environmental risks such as ground water pollution and odor problems. ...
... As a typical lignocellulosic feedstock, DGW contains high content of holocellulose and lignin [2]. Efficient pretreatment plays a key role in the utilization of carbohydrates by altering the structural and chemical composition in lignocellulosic feedstock. ...
... Structural sugars, lignin, and ash were measured by using the standard method recommended by National Renewable Energy Laboratory (NREL) [15]. The starch content was measured by hydrolyzing 5 g samples in 100 mL of 2.5% (w/v) HCl at 100°C for 3 h and determining the release of glucose [2]. The lipid was extracted by using diethyl ether with a Soxtec system HT2 (Foss, Hillerod, Denmark) according to the instruction manual, which refers to AOAC 920.39 B. The concentrations of volatile fatty acids (VFAs) were determined by a post label method, using high-performance liquid chromatography (HPLC) equipped with a UV detector (at 450 nm) and a column of Shimpack SCR-101H (Shimadzu, Japan) [16]. ...
Distilled grain waste (DGW) eluted from the Chinese liquor making process poses potential serious environmental problems. The objective of this study is to evaluate the feasibility of converting DGW to biogas by thermophilic dry anaerobic digestion. To improve biogas production, the effects of dilute H2SO4 and thermal pretreatment on DGW were evaluated by biochemical methane potential (BMP) tests. The results indicate that 90 °C thermal pretreatment provided the highest methane production at 212.7 mL/g-VTSadd. The long-term thermophilic dry anaerobic digestion process was conducted in a 5-L separable flask for more than 3 years at a volatile total solid (VTS) loading rate of 1 g/kg-sludge/d, using synthetic waste, untreated and 90 °C thermal pretreated DGW as the feedstock, respectively. A higher methane production, 451.6 mL/g-VTSadd, was obtained when synthetic waste was used; the methane production decreased to 139.4 mL/g-VTSadd when the untreated DGW was used. The 90 °C thermal pretreated DGW increased the methane production to 190.5 mL/g-VTSadd, showing an increase of 36.7% in methane production compared with that using untreated DGW. The microbial community structure analysis indicates that the microbial community in the thermophilic dry anaerobic digestion system maintained a similar structure when untreated or pretreated DGW was used, whereas the structure differed significantly when synthetic waste was used as the feedstock.
... Distilled grain waste (DGW) is the major byproduct obtained from the Chinese spirit-making process. It is discharged during the distillation process and consists of fermented grains, such as sorghum, corn, wheat and rice, along with rice husk (Tan et al., 2014). Approximately 25 million tons of DGW are generated every year in China (Zhang et al., 2013a,b). ...
... The moisture content of the raw DGW material was 61.68%, which was slightly higher than the optimal range (50-60% moisture content) for composting (Gajalakshmi and Abbasi, 2008). The VS content in the DGW material was higher at 88.77% (dry basis), which was attributed to higher contents of carbohydrate polymers (cellulose, hemicellulose and starch) and lignin (Tan et al., 2014). The raw DGW material had a low pH of 3.5. ...
... The raw DGW material had a low pH of 3.5. Usually, the Chinese spirit-making process is conducted in an open pit containing various microbial groups (Zhang et al., 2013a,b;Tan et al., 2014). Ethanol fermentation as well as lactic acid fermentation occur during this process, thus the end-product was rich in VFAs, especially lactic acid (74.04 g·kg −1 -TS). ...
