Fermentation Of Waste Research Articles

Influence of Inoculum Thermal Pretreatment Time on Hydrogen Production in Dark Fermentation

Dark fermentation (DF) of kitchen waste (KW) is a promising technology for the production of renewable biohydrogen. It can be both a method of obtaining clean energy and a sustainable waste management. Despite its potential, this process requires further research to improve efficiency. The aim of the research was to test the effect of thermal pretreatment of the inoculum on H2 and volatile fatty acids (VFAs) production in the DF process. The process was carried out at 37 °C, in batch mode. The digested sludge from the Group Wastewater Treatment Plant in Lodz was used as inoculum. KW from households was used as substrate. The inoculum was pre-treated at 70 °C for 15 and 30 min. Two control reference experiments were also used. The first without the inoculum, and the second without heating the inoculum. The thermal pretreatment inhibited methane production and increased hydrogen production. After the thermal pretreatment, the amount of CO2 produced during the process decreased compared to the bioreactor without inoculum pretreatment. Additionally, the main VFAs in the samples with pretreated inoculum were acetic and butyric acids, which are associated with hydrogen production in the biochemical pathways of the DF process. However, the time of thermal pretreatment had no significant effect on H2 production.

The Effect of Probiotic-Induced Fermentation of Restaurant Waste on the Growth of Common Carp (Cyprinus carpio) Fry

The study explores using the fermentation process to convert organic restaurant waste into fish feed, a promising solution for aquaculture. The aim is to determine the best type and dosage of probiotics for fermenting restaurant waste (FRWM) and evaluate their impact on common carp (Cyprinus carpio) fry growth. Three commercial probiotics (P1, P2, and P3) were used at an 8% concentration for fermenting the waste. The best result from the fermentation trial was tested as feed containing different FRWM proportions: 0% (TA), 10% (TB), 20% (TC), 30% (TD), and 40% (TE) with 30% protein content. The trial lasted 42 days, assessing waste chemical composition before and after fermentation, growth rate, amylase and protease activity, feed conversion, survival rate, and water quality. Results showed P1 was most effective, increasing FRWM protein content by 84.25% and reducing crude fiber and fat by 15.17% and 3.94%, respectively. TE (40% FRWM) yielded the best outcomes, with fry common carp achieving a 1.05% daily growth rate and a feed conversion ratio of 0.80, indicating efficient feed utilization. TC (20% FRWM) exhibited the highest survival rate at 88.33%. The inclusion of FRWM influenced amylase activity, increasing enzyme levels and improving feed efficiency and growth rate. In conclusion, using FRWM, fermented with P1 probiotics, showed significant improvements in its composition, leading to enhanced fish growth and feed utilization. The 40% FRWM diet demonstrated the best fish growth rate and feed conversion performance. These findings support using fermented restaurant waste as sustainable and nutritious fish feed in aquaculture.

Valorization of straw biomass into lignin bio-ink, bacterial cellulose and activated nanocarbon through the trade-off alkali-catalyzed glycerol organosolv biorefinery

Integrated lignocellulosic biorefinery that transforms low-value lignocellulose into multiple value-added products is crucial for a low-carbon sustainable development. Herein, a one-pot alkali-catalyzed glycerol organosolv (ALGO) pretreatment-based integrated biorefinery process to directionally produce lignin bio-inks, bacterial celluloses (BCs), and activated nanocarbons (ANCs) was proposed. ALGO pretreatment could modify the structure of dissolved lignins by glycerolysis. The extracted lignin fragments with high-purity (>90 %), uniform with low molecular weight (2500–4000 of Mw), and abundant hydrophilic aliphatic –OH were promising candidates in 3D-printable inks preparation. The glycerolysis reaction during ALGO process also enabled pretreated substrates toward high hydrolyzability and protected pretreatment liquor from generating fermentable inhibitors, making the solid fractions more liable for enzymatic deconstruction and microbial fermentation. Without any detoxification treatments, hydrolysates from ALGO pretreated substrates were used directly as carbon sources for BCs production, resulting in the BC yields were 56 % higher than that of the commercial glucose. The enzymatic hydrolysis residue and BC fermentation waste liquid were synthesized into ANCs via a facile carbonization process, which could further increase the value of ALGO biorefinery. Calculations showed that this ALGO integrated strategy rendered the conversion of ∼75 % lignins in pretreatment liquor to bio-inks and nearly 100 % solid fractions to BCs and ANCs. Unlike the conventional “lignin-first” route to obtain high-purity cellulose by sacrificing the value-adding conversion ability of by-products, the designed technical route in this work achieved a good trade-off between fractionation ability and subsequent conversion potential, inspiring further exploration of the technical correlation between biomass fractionation and bioproduct processing.

Optimization of Clostridium beijerinckii semi-solid fermentation of rape straw to produce butyric acid by genome analysis

Butyric acid is a volatile saturated monocarboxylic acid, which is widely used in the chemical, food, pharmaceutical, energy, and animal feed industries. This study focuses on producing butyric acid from pre-treated rape straw using simultaneous enzymatic hydrolysis semi-solid fermentation (SEHSF). Clostridium beijerinckii BRM001 screened from pit mud of Chinese nongxiangxing baijiu was used. The genome of C. beijerinckii BRM001 was sequenced and annotated. Using rape straw as the sole carbon source, fermentation optimization was carried out based on the genomic analysis of BRM001. The optimized butyric acid yield was as high as 13.86 ± 0.77 g/L, which was 2.1 times higher than that of the initial screening. Furthermore, under optimal conditions, non-sterile SEHSF was carried out, and the yield of butyric acid was 13.42 ± 0.83 g/L in a 2.5-L fermentor. This study provides a new approach for butyric acid production which eliminates the need for detoxification of straw hydrolysate and makes full use of the value of fermentation waste residue without secondary pollution, making the whole process greener and more economical, which has a certain industrial potential.Graphical

Soluble carbon source recovery using preconditioning coagulants for applicable short-term fermentation of waste activated sludge in WWTPs

A huge production of waste activated sludge (WAS) has been a burden for wastewater treatment plants (WWTPs) with high disposal cost and little benefit back to wastewater purification. The short-chain fatty acids (SCFAs) produced by a short-term acidogenic fermentation of WAS before methane production have been proven to be a high-quality carbon source available for microbial denitrification process. The dual purpose of full recovery of fermentation liquid products and facilitating disposal of residual solid waste necessitate an efficient solid-liquid separation process of short-term fermentation liquid. The transformation and loss of various soluble carbon sources between solid and liquid are very important issues for carbon recovery efficiency when combining short-term fermentation and sludge dewatering in WWTPs. Here we testified the three conventional preconditioning coagulants, Polyferric Sulfate (PFS), Poly Aluminum Chloride (PAC) and Polyacrylamide (PAM), to improve the efficiency of subsequent solid-liquid separation. The results show that conversion yield of SCFAs in the liquid phase of sludge after short-term fermentation was 195 mg COD/g VSS, when using the coagulants PFS, PAC, and PAM for recovery, the recovery ratio was 79.5%, 82.0%, and 85.9%, respectively, while the dewaterability could be improved after preconditioning short-term fermentation sludge. The complexation of Al3+/Fe3+ in metal coagulants with carboxyl groups of SCFA demonstrated by Density Functional Theory calculation led to small part of soluble carbons co-migration to the solid phase, mainly a loss of high molecular weight organic compounds (carbohydrate, proteins, humic acids), while the application of PAM had little impact on carbon recovery. Economic calculations further showed PAM preconditioning short-term fermentation liquid of WAS could achieve higher recovery benefits.

Corrosion Assessment of Metals in the Presence of Food Waste Fermentation Solution Through the Experimental Study

This paper describes an experimental study on the corrosion assessment of metals in the food waste fermentation solution. The corrosive degree of metals under different submersion conditions is assessed through the weight loss method. The experimental results indicate that HT200, Q345B, and 45 steel are rapidly corroded (weight loss values over 80, 221 mg/m2 after 192 hours). Although 304 shows a better corrosion-resistant ability, it is slightly corroded (weight loss: 1, 782 mg/m2 after 192 hours) under the interval submersion condition. The food waste treatment facilities, especially pipelines, and bioreactors should avoid iron-based materials.

The Effect of Polyglutamic Acid Produced from Glutamic Acid Wastewater on Maize Growth

This experiment uses polyglutamic acid water-soluble fertilizer produced from glutamic acid fermentation waste liquid as the experimental fertilizer to study its impact on maize yield and quality in maize cultivation. The results showed that compared to farmers who are accustomed to fertilization, the application of the new water-soluble polyglutamic acid fertilizer reduced the bald head length of corn by 0.7 cm; The weight of 100 grains of corn increased by 0.7g, resulting in an increase of 26.7 kilograms of corn per mu, with a yield increase of 5%.

Revalorization of beer brewing waste as an antifungal ingredient for bread biopreservation

This study assesses the potential revalorization of beer bagasse (BB), an important food industry waste, as antifungal ingredient in bread, by lactic acid bacterial (LAB) fermentation of this food waste. Initially, in vitro studies of the metabolite and antifungal activity were performed for the preparation of a microbial culture medium for the LAB. The culture medium with a 20% BB was determined as the optimal for the bacterial growth. Therefore, bread was prepared with a 5% and 10% (w/w) of a dried powder of this fermented culture medium as ingredient. The fermentation and heat treatment during baking did not compromise the antifungal metabolites in the bread. In the trials of the augment of the shelf-life the bread with a 10% concentration of the ingredient extended the shelf life of the bread by a 1 day and 3 days against Aspergillus flavus and Penicillium commune, respectively, compared to a regular bred. When studying the mycotoxin production in the bread the addition of the ingredient at a 10% concentration resulted in an 86% reduction in aflatoxin concentration compared to the control bread. Moreover, this ingredient did not importantly deteriorate the technological parameters of the bread.

Enhanced Food Waste Chain Elongation for Caproate Production: Role of Inorganic Carbon and Optimization Strategies

In this study, the role of inorganic carbon in chain elongation fermentation was investigated by examining its effects at different carbonate concentrations. The results demonstrated that higher yield of caproate (6.3±0.3 g/L - 7.4±0.2 g/L) was achieved with a NaHCO3 concentration of 2.5-5.0 g/L. Building upon these findings, a chain elongation process for food waste was developed. The caproate productions of control, CO2 and Na2CO3 trials were 4.6±0.2 g/L, 7.3±0.1 g/L, and 8.3±0.2 g/L, respectively. Chain elongation fermentation of food waste (1t TS) with Na2CO3 enhancement could synthesize 116.9 kg of caproate and 72.5 kg of carbon could be converted in caproate, accounting for 15.5% of the total organic carbon in the food waste. This study provided a comprehensive exploration of the chain elongation process for food waste, offering insights for further optimization and enhancement of food waste chain elongation performance coupling inorganic carbon utilization.

Fermentation of waste water from agar processing with Bacillus subtilis by metabolomic analysis.

Fungal infection has become a major threat to crop loss and affects food safety. The waste water from agar processing industries extraction has a number of active substances, which could be further transformed by microorganisms to synthesize antifungal active substances. In this study, Bacillus subtilis was used to ferment the waste water from agar processing industries extraction to analyze the antifungal activity of the fermentation broth on Alternaria alternata and Alternaria spp. Results showed that 25% of the fermentation broth was the most effective in inhibited A. alternata and Alternaria spp., with fungal inhibition rates of 99.9% and 96.1%, respectively, and a minimum inhibitory concentration (MIC) was 0.156μg/mL. Metabolomic analysis showed that flavonoid polyphenols such as coniferyl aldehyde, glycycoumarin, glycitin, and procyanidin A1 may enhance the inhibitory activity against the two pathogenic fungal strains. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that polyphenols involved in the biosynthesis pathways of isoflavonoid and phenylpropanoid were upregulated after fermentation. The laser confocal microscopy analyses and cell conductivity showed that the cytoplasm of fungi treated with fermentation broth was destroyed. This study provides a research basis for the development of new natural antifungal agents and rational use of seaweed agar waste. KEY POINTS: • Bacillus subtilis fermented waste water has antifungal activity • Bacillus subtilis could transform active substances in waste water • Waste water is a potential raw material for producing antifungal agents.

Regulation of hydraulic retention time on caproic acid production via two-phase anaerobic fermentation of Chinese cabbage waste with autopoietic electron donors

The effects of hydraulic retention time (HRT) on the performance of two-phase anaerobic fermentation for caproic acid production from Chinese cabbage waste (CCW) were investigated. In the electron donor phase, yeast was inoculated to achieve efficient autopoietic ethanol, providing electron donors for the chain elongation process. Shorter HRT led to drastic fluctuations in microorganisms, thus resulting in lower acid yields at HRT of 6 days. At HRT of 10 days, the balanced collaboration of various key bacteria avoided the accumulation of intermediate by-products, and the caproic acid production reached 4660 mg COD/L, which was 119.5% and 154.8% higher than that at HRTs of 6 and 14 days, respectively. At HRT of 14 days, the low ethanol loading rate resulted in ethanol excessive-oxidation to acetic acid. Acetic acid accounted for 41.5% of the total product, while the selectivity of caproic acid was only 15.3%. The main contributor to the production process of caproic acid was Caproiciproducens, while the Ruminalococcaceae also played a role in the process. This study provided a theoretical basis for the efficient production of caproic acid through continuous fermentation with autopoietic electron donors.

Mathematical Model of Biomethane Yield at Anaerobic Methane Fermentation of Organic Wastes: Influence of Various Parameters and Factors

Mathematical Model of Biomethane Yield at Anaerobic Methane Fermentation of Organic Wastes: Influence of Various Parameters and Factors

Modeling of biotechnological objects

The article discusses the system of modeling biotechnological objects and biogas production in the process of fermentation of various agricultural wastes. The complexity of automation of biotechnological processes, which consists in the lack of sufficient knowledge about the phenomena associated with the process of fermentation and the synthesis of target materials, is shown. Solutions to control problems using intelligent methods, intelligent control systems, based on fuzzy logic and on the basis of on the basis of neural network technologies, which have proven themselves in the control of complex objects with parameters that vary widely, as well as the analysis of algorithms for the operation of programmable logic controllers that perform the functions of regulators in the systems of operational control of complex processes, adaptive neuro-fuzzy architecture. Distributed in management decision support systems, it is made in the form of a six-layer neural structure, i.e. systems with neuro-fuzzy regulators, are able to largely meet the modern requirements of the designed systems, as a result of which the systems, using the technology of synthesis of intelligent control algorithms, can optimize complex circuits of automatic control systems.

QUALITY OF ECO ENZYME PRODUCED THROUGH A FERMENTATION PROCESS IN VARIOUS "TEMPE" YEAST CONCENTRATIONS

Organic waste that accumulates and is not adequately managed causes disease and environmental problems. Therefore, one method to solve the problems is to convert it into eco enzyme, a liquid created from the fermentation of organic waste, specifically vegetable and fruit peels, sugar, and water. Anaerobic fermentation is utilized to produce eco enzymes, with yeast added to shorten the fermentation time. The goal of this research is to determine the effect of "tempe" yeast concentration on the quality of eco enzymes. Eco enzyme was made from brown sugar, fruit peels (oranges and melons), and water in a 1:3:10 ratio. "Tempe" yeast concentrations of 1, 2, 3, 4, and 5 %w/v were used in the fermentation process for producing eco enzyme. The eco enzyme products were examined by analyzing pH value, acetic acid content, Total Dissolved Solids (TDS) value, organoleptic properties (aroma and color), and protease enzyme activity. The pH and TDS values of eco enzyme products increased as the concentration of "tempe" yeast increased. The results showed that eco enzyme products have pH values in the range of 3.5-4, acetic acid content of 0.81-1.08 %v/v, TDS value of 1000-2000 ppm, with fermented and orange aroma and a bright yellow color. According to the results, the addition of 3 %w/v "tempe" yeast in the production of eco enzyme was selected as a sample tested for protease enzyme activity and a clear zone was identified around the colony, indicating that there was protease enzyme activity.

The potential of local orange peel-derived eco-enzymes in producing indole acetic acid

Background: Ecoenzymes, created from the fermentation of organic citrus waste, offer a sustainable method to produce Indole Acetic Acid (IAA), a phytohormone vital for plant growth. This study investigates the potential of these ecoenzymes in promoting sustainable agriculture. Objective: This study aims to evaluate the capacity of ecoenzymes derived from local citrus organic waste to synthesize IAA hormones. Methods: The ecoenzyme was extracted from fruit powders and centrifuged to separate the supernatant. One ml of ecoenzyme supernatant was then mixed with 2 ml of Salkowski reagent and incubated for 12 hours at room temperature in the dark to facilitate reaction. The presence and concentration of IAA were determined using spectrophotometry at a wavelength of 530 nm, while total protein levels were measured using the Warburg-Christian method. Results: ecoenzymes from local citrus sources contain IAA, with the highest concentration observed in sample 7A (30.26 µg/ml). The ecoenzyme exhibited favorable characteristics, including an average degree of acidity of 3.55, and the highest total protein content was found in sample 2A (144.277 mg/mL). Conclusion: Ecoenzymes from local orange peels successfully produce IAA, supported by fermentation-induced microbial activity and acidic conditions. This highlights their potential in sustainable agriculture.

The potential of local orange peel-derived eco-enzymes in producing indole acetic acid

Background: Ecoenzymes, created from the fermentation of organic citrus waste, offer a sustainable method to produce Indole Acetic Acid (IAA), a phytohormone vital for plant growth. This study investigates the potential of these ecoenzymes in promoting sustainable agriculture. Objective: This study aims to evaluate the capacity of ecoenzymes derived from local citrus organic waste to synthesize IAA hormones. Methods: The ecoenzyme was extracted from fruit powders and centrifuged to separate the supernatant. One ml of ecoenzyme supernatant was then mixed with 2 ml of Salkowski reagent and incubated for 12 hours at room temperature in the dark to facilitate reaction. The presence and concentration of IAA were determined using spectrophotometry at a wavelength of 530 nm, while total protein levels were measured using the Warburg-Christian method. Results: ecoenzymes from local citrus sources contain IAA, with the highest concentration observed in sample 7A (30.26 µg/ml). The ecoenzyme exhibited favorable characteristics, including an average degree of acidity of 3.55, and the highest total protein content was found in sample 2A (144.277 mg/mL). Conclusion: Ecoenzymes from local orange peels successfully produce IAA, supported by fermentation-induced microbial activity and acidic conditions. This highlights their potential in sustainable agriculture.

Preparation of Li3V2(PO4)3@C composites using aluminum chloride catalyzed fermentation residue of bioethanol production with reed as carbon source for long life Li-ion batteries

The capability and longevity of lithium-ion batteries (LIBs) are heavily influenced by simultaneously increasing the lithium-ion extraction/insertion dynamics and enhancing the construction stabilization of Li3V2(PO4)3 (LVP) positive electrode material. With the goal to improve the battery's stability, fermentation residues rich in functional groups that contain oxygen might be wrapped around LVP. This is the first time, to our knowledge, that high-performance LVP cathode materials have been created utilizing leftover fermentation waste as a carbon source. More crucially, due to the promoted invertible V3+/V4+ redox conjugate pair created by oxygen groups coinciding with the improved Li+ dynamics properties, the top-performing material generated an excellent primal discharging capability of 131.9 mA h/g (approaching the projected performance) at 0.5 C. Additionally, after 500 cycles, the improved battery exhibits higher capacity retention of 95%.

Co-pretreatment (calcium peroxide + freeze) to improve anaerobic fermentation of waste activated sludge: Method optimization and mechanism insights

The reduction, harmlessness, and recycling of waste-activated sludge (WAS) can be accomplished by anaerobic fermentation, where sludge disintegration is the key speed-limiting process. Co-pretreatment, as a derivative of pretreatment, has attracted more and more attention. However, obtaining optimal co-pretreatment conditions is difficult. Response surface methodology (RSM) can combine statistical analysis with mathematics to optimize the parameters. Therefore, in the current work, RSM optimization for CaO2-freezing co-pretreatment conditions to improve the production of short-chain fatty acids (SCFAs) from WAS was carried out using the Box-Behnken Design based on Design Expert software. We obtained the optimal values of three pretreatment parameters: −18 °C freezing temperature, 48.6 h freezing time, and 0.19 g CaO2/g VSS addition. After 5 days of fermentation, the maximum cumulative yield of SCFAs was 162.34 mg COD/g VSS. CaO2-freezing co-pretreatment promoted the solubilization and release of organic matter in WAS during anaerobic fermentation, which not only provided more organic matter for the subsequent production of SCFAs but also improved the methane production capacity in the anaerobic digestion stage. 16S rRNA genes sequencing revealed that the abundance of SCFAs-producing bacteria (i.e., Macellibacteroides and Proteiniclasticum) was significantly enriched in the fermentation tank after CaO2-freezing co-pretreatment. All in all, this study successfully optimized the co-pretreatment conditions based on RSM, providing new insights and effective solutions for the environmentally friendly and efficient realization of solid waste recycling.

Fermentation and valorization of watermelon (Citrullus lanatus) rind wastes into livestock feed using Aspergillus niger and Mucor sp.

Agro-industrial wastes pose environmental health hazards to humans and animals; yet, they are abundant, readily availabile and cheap, and therefore provide opportunities for their valorization with microorganisms to produce value-added, nutrient-rich animal feed. This study (i) determined, in vitro, optimum growth conditions for Aspergillus niger and Mucor sp. and (ii) subsequently evaluated their ability to ferment and valorize watermelon wastes for protein enhancement. Changes in protein contents of sterilized and unsterilized watermelon substrates were determined after 5, 10, and 15 days of fermentation with mono- and co-cultures of A. niger and Mucor sp. at 25 °C. Different growth conditions (pH, temperature, different concentrations of ammonium nitrate, sodium nitrate, urea, sodium chloride and thiamine) of synthetic media variously supported mycelial growth of A. niger and Mucor sp., either as mono- or co-culture; optimum growth conditions were selected for fermentation of watermelon wastes. Protein contents of sterilized and unsterilized watermelon substrates were enhanced by fermentation: (i) percentage increase in protein contents of sterilized watermelon fermented with mono-cultures of A. niger, Mucor sp. and co-culture of A. niger and Mucor sp. were 35.91, 18.94 and 22.18 %, respectively; (ii) protein contents in unsterilized watermelon substrates also increased by 23.94, 9.49, and 14.88 % for mono-cultures of A. niger and Mucor sp. and their co-culture, respectively. Overall, the observed trend in the increase of protein contents in the sterilized and unsterilized substrates by the test fungi was: mono-culture of A. niger > co-culture of A. niger and Mucor sp. > mono-culture of Mucor sp. Crude fat, fiber and ash contents significantly (p ≤ 0.05) decreased in both sterilized and unsterilized watermelon substrates, whereas the carbohydrate content increased significantly (p ≤ 0.05) in the substrates. These findings highlight the potential of watermelon waste as valuable bioresource and feedstock for valorization into livestock feed through fungal biotechnology. Future works to augment findings are suggested.

Оценка применимости почвогрунтов, произведённых из твёрдых отходов для выращивания лекарственных растений

The production of artificial soils – products of solid-phase fermentation of municipal solid waste – is one of the main areas of processing waste from megacities containing organic substances and is a “green” alternative to their incineration or burial. The possibility of using products of solid-phase fermentation of waste for growing medicinal plants was studied using the examples of mountain savory (Satureja montana L.), common basil (Ocimum basilikum L.), marshmallow (Althaea officinalis L.), oregano (Origanum vulgare L.). It was revealed that the optimal germination of plants occurs on the artificial soils “Klasmann Substrates Select” and “Grunt ECO” and it is comparable to the control soil of field crop rotation.The changes in the biochemical parameters of plants (enzyme activity, chlorophyll content) grown on soils under normal conditions, under the influence of heavy metals and at low temperatures are shown. High chlorophyll content was noted in all studied plants, however, in mountain savory grown on the “Veltorf” substrate, destructive phenomena were revealed, expressed in a decrease in the content of chlorophyll a with a simultaneous increase in the content of chlorophyll b. The activity of catalase and acid phosphatase enzymes in the studied plants is within normal limits. The effect of unfavorable factors – low temperature and heavy metals – leads to an increase in enzyme activity, which is a sign of the formation of adaptation. When assessing the germination of plants of various species and their biochemical parameters, it was found that the domestic soil of the Grunt ECO company is optimal for growing medicinal plants and can be used for medicinal plant growing purposes.