Application Effect of Cassava Starch Anaerobic Fermentation Liquid on Watermelon Production

In order to find out a new way for environment-friendly and resourcelized utilization of cassava starch processing wastewater, the cassava starch anaerobic fermentation liquid was applied in watermelon production, and its effects on the growth and development, yield and fruit quality of watermelon were investigated. The results showed that the cassava starch anaerobic fermentation liquid significant- ly promoted the vegetative and reproductive growth and improved the yield and fruit quality of watermelon. Compared with conventional fertilization, the application of cassava starch anaerobic fermentation both with COD concentration of 1 200 mg/L according to the amount of 150 t/hm2 promoted the growth of vines and leaves of watermelon plants, brought forward the flowering, fruiting and harvest of watermelon and significantly increased the fruit number, fruit weight, yield, fruit size, fruit shape index, soluble solid content, soluble sugar content, soluble protein content and Vita- min C content of watermelon. At the same time of improving the yield and quality of watermelon, cassava starch anaerobic fermentation liquid was turned into treasure as a liquid fertilizer. This study provides a new ideal for the yield and quality im- provement of watermelon and the wastewater treating of starch factories.

Effects of Application of Cassava Alcohol Anaerobic Fermentation Liquid and Mulching of Film on Overwintering and Next Year's Growth and Yield of Banana

The effects of application of cassava alcohol anaerobic fermentation liquid and mulching of film on overwintering and next year's growth and yield of banana were investigated in this study.The results showed that the application of cassava alcohol anaerobic fermentation liquid with COD concentration of 1 200-2 000 mg/L(900 m^3/hm^2) and mulching of film significantly increased the soil organic matter and available potassium contents in banana orchard,improved the cold resistance of banana seedlings,increased the pseudostem height,pseudostem circumference,green leaf number and chlorophyll content of next year's banana seedlings,brought the flower bud emergence period and harvest period forward,and significantly increased the yield per plant.

Consideration and development of anaerobic fermentation equipment on solid organic rejectamenta

This article, based on investigation and analysis, existed anaerobic fermentation equipment, with a view to the production of high-latitude area, pointed out the thought of exploiting efficient anaerobic fermentation equipment, including： the settting independent equipment of acidogenic phase and methanogenic phase; the applying conbination of AF and UASB in methanogenic phase; adopting efficient sludge inverse flowing equipment and the technique of flora enrichment, and efficient method of saving energy and thermal retardation; adopting autocontrol which could make the equipment run efficiently and stably.

Microbial Diversity and Key Metabolic Pathways in Lignite-Promoted Anaerobic Fermentation with Residual Sludge

To enhance methane production efficiency in lignite anaerobic digestion and explore new ways for residual sludge utilization, this study employed the co-fermentation of lignite and residual sludge for biomethane conversion. The bacterial colony structure, metabolic pathways, and interactions between residual sludge and lignite in anaerobic methanogenic fermentation with different mass ratios were analyzed using macrogenomics sequencing. This study aimed to explore the mechanisms involved in the co-anaerobic fermentation of lignite and residual sludge. The results indicated that the addition of sludge enhanced the metabolic pathways in hydrolysis acidification, hydrogen-acetic acid production, and methanation phases. Notably, the enhancement of acetate- and carbon dioxide-nutrient metabolic pathways was more pronounced, with increased activity observed in related enzymes such as acetic acid kinase (k00925) and acetyl coenzyme synthetase (K01895). This increased enzymatic activity facilitated the microbial conversion of biomethane. The results of the study indicated that the sludge exhibited a promotional effect on the methane produced through the anaerobic fermentation of lignite, providing valuable insights for lignite and residual sludge resource utilization.

Effect of vacuum negative pressure aerobic hydrolysis pretreatment on corn stover anaerobic fermentation

Lignin degradation restricts corn stover anaerobic fermentation efficiency.The vacuum negative pressure aerobic hydrolysis pretreatment of corn stover was tested,and the optimal combined pretreatment conditions were presented in this paper.Because of the physical characteristics of light weight and large specific porosity of stover,it led to the formation of a scum layer during the fermentation process and thus reduced the gas production rate.In the pretreatment design,the vacuum conditions(0.02-0.08 MPa)and dwell time(5-20 min)were selected to see the changes of volumetric weight,swelling and specific porosity of corn stover,resulting in an increase of the volumetric weight by 7.18%-28.72%,an increase of the swelling by 3.18%-58.59%,and a decrease of the specific porosity by 9.34%-38.59%,as compared with the CK group.Continuous vacuum negative pressure treatment could discharge the air inside the stover destroy the microstructure,and cause the stover to settle more easily during the aerobic hydrolysis process.The optimal aerobic hydrolysis temperature and time were determined to be 39°C and 12.65 h,respectively.With the optimal pretreatment,the corn stover anaerobic fermentation test realized a cumulative methane yield of 260.44 mL/g VS,22.71%higher than CK group;meanwhile,the hydraulic retention time was shortened by 32.39%.

Microorganism population in two-phase anaerobic fermentation of separated liquid of dairy manure

In order to reduce incomplete fermentation caused by high substrate viscosity and low mass transfer efficiency during fermentation process,batch and two-phase anaerobic fermentation experiments were conducted in this study.Dairy manure was separated by using solid-liquid separator firstly.Separated liquid(SL)and diluted dairy manure(DDM)as raw materials were evaluated in terms of gas production performance for both batch and two-phase anaerobic fermentation.The microorganism population was characterized by scanning electron microscope(SEM)and Denaturing Gradient Gel Electrophoresis(DGGE).The results showed that Volatile Solid(VS)methane yield of SL was 124.51 L/kg VS,which was 2.09 times higher than that of DDM(59.50 L/kg VS)in batch anaerobic fermentation.The Bacteroides and Veillonella with higher activity were the majority microorganism population in acidogenic phase,whereas the Firmicutes and Corynebacterium with methanogenic properties became the predominant microorganism population in methanogenic phase.This study achieved the phase separation and improved the gas production performance.

Effects of urea ammonia pretreatment on the batch anaerobic fermentation efficiency of corn stovers

In order to enhance the biogas production and provide nitrogen sources for the growth of microorganisms,experiments on urea ammonia pretreatment of corn stovers were implemented at(35±1)°C to investigate the effects of urea ammonia pretreatment on the batch anaerobic fermentation efficiency of corn stovers.This study assessed the effects of urea ammonia contents(2%,4%,and 6%)and moisture contents(30%,50%,70%and 90%)on the physical structures of lignocelluloses and the efficiency of biogas production from anaerobic fermentation of corn stovers.The results indicated that the methane production reached 230.31 mL/g VS(volatile solids)at pretreatment with 4%urea ammonia and 70%moisture contents for the batch anaerobic fermentation,which was 26.6%higher than that of the untreated group.The degradation rates of cellulose and hemicellulose were 66.34%and 75.47%after the anaerobic fermentation,respectively,which were about 22.6%and 20.9%higher than that of the untreated group,respectively.Thus,it was concluded that urea ammonia pretreatment can improve the efficiency of biogas production from anaerobic fermentation of corn stovers.

Effect of normal and strict anaerobic fermentation on physicochemical quality and metabolomics of yogurt

Generally,yogurts on the market are usually anaerobic fermentation,but oxygen can be still dissolved in the production process,which is actually not strict anaerobic.This study explored the multiple quality indicators and the metabolomic analysis of yogurts fermented by Lactobacillus bulgaricus and Streptococcus thermophilus using two fermentation methods,namely,strict anaerobic and normal fermentation.The changes in flavor substances in yogurts,including 17 free amino acids,17 fatty acids,and 7 response value,were detected using principal component and multi factor analyses.Based on the results of the comparisons between basic physical and chemical indicators,strict anaerobic fermentation increased the growth and acidification of the two bacteria,the response value of sourness,umami and richness.Strict anaerobic fermentation increased the free amino acid(Fold change=1.53)and short chain fatty acid levels(Fold change=1.73),and reduced the polyunsaturated fatty acid(Fold change=0.51)levels.Furthermore,metabolomic analysis based on UPLC-Triple TOF-MS/MS showed that 92 differential metabolites were screened;45 differential metabolites were increased and 47 were decreased.The results revealed that strict anaerobic fermentation was beneficial to metabolic changes and nutritional indicators of yogurt,which may be as indicators of valuable reference to improve dairy fermentation process.

Synergetic Bioproduction of Short-Chain Fatty Acids from Waste Activated Sludge Intensified by the Combined Use of Potassium Ferrate and Biosurfactants

The synergetic effect and underlying mechanism of potassium ferrate(PF)with tea saponin(TS,a biosurfactant)in producing short chain fatty acids(SCFAs)from anaerobic fermentation of waste activated sludge(WAS)were explored in this work.Experimental results showed that 0.2 g PF(g TSS)^(-1)(total suspended solid)combined with 0.02 g TS(g TSS)^(-1) could further improve SCFAs’production,and the maximum SCFAs content reached 2008.7 mg COD L^(-1),which is 1.2 and 4.5 times higher than those with PF and TS individually added,respectively,and 5.3 times higher than that of blank WAS on Day 12.In the model substrates experiments,the degradation rates of bovine serum albumin and dextran with combination of PF and TS were 41.3%±0.1% and 48.5%±0.06%,respectively,on Day 3,which are lower than those in blank WAS(with degradation rates of 72.3%±0.5%and 90.3%±0.3%).It was revealed that the oxidative effect of PF and the solubilization of TS caused more organic matters to be dissolved out from WAS,providing a large number of biodegradable substances for subsequent SCFAs production.While WAS pretreated with the combination of PF and TS,the relative abundances of Firmicutes increased from 6.4%(blank)to 38.6%,and that of Proteobacteria decreased from 41.8%(blank)to 21.8%.The combination of PF and TS promoted the hydrolysis process of WAS by enriching Firmicutes,and then increased acetic acid production by inhibiting Proteobacteria that consumed SCFAs.Meanwhile,at the genus level,acidogenesis bacteria(e.g.,Proteiniclasticum and Petrimonas)were enriched whereas SCFAs consuming bacteria(e.g.,Dokdonella)were inhibited.

Effect of Sodium Ion Concentration on Hydrogen Production from Sucrose by Anaerobic Hydrogen-producing Granular Sludge

This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L^-1（Na^＋）, on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the optimum sodium ion concentration [1000-2000mg·L^-1（Na^＋）] for hydrogen production at 37℃, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6-413.1mg·L^-1.h^-1, 28.04-28.97ml·g^-1, 7.52-7.83ml·g^-1.h^-1, respectively. The specific production yields of propionate, butyrate and valerate decreased with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g^-1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration.

Effect of Sodium Ion Concentration on Hydrogen Production from Sucrose by Anaerobic Hydrogen-producing Granular Sludge

This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L-1(Na+), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the opti- mum sodium ion concentration [1000—2000mg·L-1(Na+)] for hydrogen production at 37℃, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6— 413.1mg·L-1·h-1, 28.04—28.97ml·g-1, 7.52—7.83ml·g-1·h-1, respectively. The specific production yields of propionate, butyrate and valerate decreased with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g-1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration.

Design of an Expert Control System for Biogas Fermentation Process

Controlling the biogas fermentation process is the key for maintaining stable operation of biogas system and increasing gas yield. Aiming at features of biogas fermentation process and difficulties of control, a practical control scheme is proposed combining the abundant experience of biogas experts. And it discussed the structural design and hardware configuration of the expert control system, established the database and role base, and designed the control strategy of production system inference. The design scheme with ZigBee and PDA technology as core is employed so as to solve problems of environmental factor detection and data transfer management. The test result shows that the deviation of temperature is controlled within ± 0.9℃, the deviation of pH is controlled within ±0.3, the deviation of oxidation-reduction potential is controlled within ±30mV, the deviation of gas production is controlled within ± 9mL and that of methane concentration is controlled within ±4.5%. This system is easily expandable and applicable to biogas engineering at various scales.

Evaluating the impact of sulfamethoxazole on hydrogen production during dark anaerobic sludge fermentation

The impact of antibiotics on the environmental protection and sludge treatment fields has been widely studied.The recovery of hydrogen from waste activated sludge(WAS)has become an issue of great interest.Nevertheless,few studies have focused on the impact of antibiotics present in WAS on hydrogen production during dark anaerobic fermentation.To explore the mechanisms,sulfamethoxazole(SMX)was chosen as a representative antibiotic to evaluate how SMX influenced hydrogen production during dark anaerobic fermentation of WAS.The results demonstrated SMX promoted hydrogen production.With increasing additions of SMX from 0 to 500 mg/kg TSS,the cumulative hydrogen production elevated from 8.07±0.37 to 11.89±0.19 mL/g VSS.A modified Gompertz model further verified that both the maximum potential of hydrogen production(Pm)and the maximum rate of hydrogen production(R_(m))were promoted.SMX did not affected sludge solubilization,but promoted hydrolysis and acidification processes to produce more hydrogen.Moreover,the methanogenesis process was inhibited so that hydrogen consumption was reduced.Microbial community analysis further demonstrated that the introduction of SMX improved the abundance of hydrolysis bacteria and hydrogen-volatile fatty acids(VFAs)producers.SMX synergistically influenced hydrolysis,acidification and acetogenesis to facilitate the hydrogen production.

Production of Biogas from Olive Mill Waste Waters Treated by Cow Manure

The olive mill waste waters (OMWW) generated from olive oil extraction is a major environmental concern since they are characterized by their role as a pollutant (high organic and mineral matters) and their pH acid. The aim of this study was to valorize (OMWW) by anaerobic fermentation in the presence of cow manure in order to produce biogas and reduce their toxic load. Many tests were carried out by fermenting (OMWW) with polyphenols in the presence of cow manure in thermophile temperatures. The performance of this treatment was valuated through measurements of biogas production and by the determination of different parameters of fermented media (pH, volume of the biogas and polyphenols).

Metabolic engineering of an industrial bacterium Zymomonas mobilis for anaerobic l-serine production

Due to the complicated metabolic and regulatory networks of l-serine biosynthesis and degradation,microbial cell factories for l-serine production using non-model microorganisms have not been reported.In this study,a combination of synthetic biology and process optimization were applied in an ethanologenic bacterium Zymomonas mobilis for l-serine production.By blocking the degradation pathway while introducing an exporter EceamA from E.coli,l-serine titer in recombinant Z.mobilis was increased from 15.30 mg/L to 62.67 mg/L.It was further increased to 260.33 mg/L after enhancing the l-serine biosynthesis pathway.Then,536.70 mg/L l-serine was achieved by removing feedback inhibition with a SerA mutant,and an elevated titer of 687.67 mg/L was further obtained through increasing serB copies while enhancing the precursors.Finally,855.66 mg/L l-serine can be accumulated with the supplementation of the glutamate precursor.This work thus not only constructed an l-serine producer to help understand the bottlenecks limiting l-serine production in Z.mobilis for further improvement,but also provides guidance on engineering non-model microbes to produce biochemicals with complicated pathways such as amino acids or terpenoids.

Effects of thermally pretreated temperature on bio-hydrogen production from sewage sludge

Hydrogen can be obtained by anaerobic fermentation of sewage sludge. Therefore, in this paper the effects of thermally pretreated temperatures on hydrogen production from sewage sludge were investigated under different pre-treatment conditions. In the thermal pretreatment, some microbial matters of sludge were converted into soluble matters from insoluble ones. As a result, the suspended solid（SS） and volatile suspended solid（VSS） of sludge decreased and the concentration of soluble COD（SCOD） increased, including soluble carbohydrates and proteins. The experimental results showed that all of those pretreated sludge could produce hydrogen by anaerobic fermentation and the hydrogen yields under the temperatures of 121℃ and 50℃ were 12.23 ml/g VS（most） and 1.17 ml/g VS （least）, respectively. It illuminated that the hydrogen yield of sludge was affected by the thermally pretreated temperatures. Additionally, the endurance of high hydrogen yield depended on the translation of microbial matters and inhibition of methanogens in the sludge. The temperatures of 100℃ and 121℃ （treated time, 30 min） could kill or inhibit completely the methanogens while the others could not. To produce hydrogen and save energy, 100℃ was chosen as the optimal temperature for thermal pretrcatment. The composition changes in liquid phase in the fermentation process were also discussed. The SCOD of sludge increased, which was affected by the pretreatment temperature. The production of volatile fatty acids in the anaerobic fermentation increased with the pretreatment temperature.

Influence of L-Cysteine Concentration on Oxidation-reduction Potential and Biohydrogen Production

The effects of L-cysteine concentration on biohydrogen production by Enterobacterium Bacterium M580 were investigated in batch cultivation.The experimental results showed that L-cysteine could enhance the cell growth,hydrogen production rate and hydrogen yield when its concentration was less than 500 mg·L-1,while it had negative effects when its concentration was higher than 500 mg·L-1.The hydrogen production was the highest 1.29 mol·mol-1(H2/glucose) when 300 mg·L-1L-cysteine was added into the culture,and the yield was 9.4% higher than that in the control.The oxidation-reduction potential(ORP) ,which was influenced by L-cysteine,also affected hydrogen production.The ORP values were in the range-300 mV to-150 mV when the L-cysteine concentration was higher than 500 mg·L-1.Although the ORP in this range was favorable for hydrogen production,it was not suitable for the biomass growth.Hence,less hydrogen was produced.When the L-cysteine concentration was lower than 500 mg·L-1,the ORP was more suitable for both biomass growth and hydrogen production.In addition,at least 91%glucose was consumed when L-cysteine was added to the culture media,compared to the 97.37% consumption without L-cysteine added.

Development of a new cleaner production process for cassava ethanol

A new cleaner production process for cassava ethanol has been developed, in which the thin stillage by-product was treated initially by anaerobic digestion, and the digestate further processed by hydrogen-form cation exchange resin before being recycled as process water to make mash for the next ethanol fermentation batch.Thus wastewater was eliminated and freshwater and energy consumption was significantly reduced. To evaluate the new process, ten consecutive batches of ethanol fermentation and anaerobic digestion at lab scale were carried out. Average ethanol production in the recycling batches was 11.43%(v/v) which was similar to the first batch, where deionized(DI) water was used as process water. The chemical oxygen demand(COD) removal rate reached 98% and the methane yield was 322 ml per gram of COD removed, suggesting an efficient and stable operation of the anaerobic digestion. In conclusion, the application of the new process can contribute to sustainable development of the cassava ethanol industry.

Potential prebiotic effects of nonabsorptive components of Keemun and Dianhong black tea:an in vitro study

Black tea is a healthy and popular tea beverage.However,its main bioactive compounds(theaflavins and thearubigins)are not easily absorbed.The aim of this study was to investigate the modulation of intestinal microbiota by the nonabsorptive components of Keemun black tea(KBT)and Dianhong black tea(DBT),and fructooligosaccharide(FOS)was selected for use in the control group.KBT,DBT,and FOS significantly increased total short-chain acid production.Specifically,FOS treatment predominantly increased the production of acetic acids and black tea treatments increased the production of acetic,propionic,and butyric acids at similar rates.Moreover,FOS exerted a strong bifidogenic effect after 24 h of fermentation;KBT and DBT increased the abundance of the beneficial genus Bacteroides and Roseburia.In summary,the nonabsorptive components of KBT and DBT could serve as novel prebiotics,the underlying mechanisms of which are quite different from those of FOS.

Effects of Ultrasonic and Acid Pretreatment on Food Waste Disintegration and Volatile Fatty Acid Production

This study aims at investigating the effects of ultrasonic and acid pretreatment on food waste( FW)disintegration and volatile fatty acid( VFA) production. Single-factor experiments are carried out to obtain optimal conditions of individual ultrasonic and acid pretreatment,and response surface method( RSM) is applied to optimize the conditions of the combination of ultrasonic and acid( UA) pretreatment. Results show that the optimal acid,ultrasonic and UA pretreatments conditions are individual pH 2,individual ultrasonic energy density of 1. 0 W / mL and the combination of ultrasonic energy density1. 11 W / mL and pH 1. 43,respectively. Correspondingly,the maximum disintegration degrees( DD) of 46. 90%,57. 38% and68. 83%are obtained by acid,ultrasonic and UA pretreatments,respectively. After optimizing pretreatment conditions,batch experiments are operated to produce VFA from raw and pretreated FW under anaerobic fermentation process. Both the maximum VFA production( 976. 17 mg COD / gV S) and VFA / SCOD( 72. 89%) are obtained with ultrasonic pretreatment, followed by UA pretreatment, non-pretreatment and acid pretreatment,respectively. This observation demonstrates that a higher acidity on acid and UA pretreatments inhibits the generation of VFA. Results suggest that ultrasonic pretreatment is preferable to promote the disintegration degree of FW and VFA production.