scholarly journals Volatile Fatty Acids (VFA) Production from Wastewaters with High Salinity—Influence of pH, Salinity and Reactor Configuration

Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 303
Author(s):  
Maria Salomé Duarte ◽  
João V. Oliveira ◽  
Carla Pereira ◽  
Miguel Carvalho ◽  
Daniela P. Mesquita ◽  
...  
Keyword(s):  
Volatile Fatty Acids ◽  
High Salinity ◽  
Raw Materials ◽  
Granular Sludge ◽  
Building Blocks ◽  
Biodiesel Production ◽  
Batch Mode ◽  
Stirred Reactor ◽  
Initial Ph ◽  
Influence Of Ph

The hydrocarbon-based economy is moving at a large pace to a decarbonized sustainable bioeconomy based on biorefining all types of secondary carbohydrate-based raw materials. In this work, 50 g L−1 in COD of a mixture of food waste, brine and wastewater derived from a biodiesel production facility were used to produce organic acids, important building-blocks for a biobased industry. High salinity (12–18 g L−1), different reactors configuration operated in batch mode, and different initial pH were tested. In experiment I, a batch stirred reactor (BSR) at atmospheric pressure and a granular sludge bed column (GSBC) were tested with an initial pH of 5. In the end of the experiment, the acidification yield (ηa) was similar in both reactors (22–24%, w/w); nevertheless, lactic acid was in lower concentrations in BSR (6.3 g L−1 in COD), when compared to GSBC (8.0 g L−1 in COD), and valeric was the dominant acid, reaching 17.3% (w/w) in the BSR. In experiment II, the BSR and a pressurized batch stirred reactor (PBSR, operated at 6 bar) were tested with initial pH 7. The ηa and the VFA concentration were higher in the BSR (46%, 22.8 g L−1 in COD) than in the PBSR (41%, 20.3 g/L in COD), and longer chain acids were more predominant in BSR (24.4% butyric, 6.7% valeric, and 6.2% caproic acids) than in PBSR (23.2%, 6.2%, and 4.2%, respectively). The results show that initial pH of 7 allows achieving higher ηa, and the BSR presents the most suitable reactor among tested configurations to produce VFA from wastes/wastewaters with high salinity.

scholarly journals Volatile Fatty Acids from Lipid-Extracted Yeast Provide Additional Feedstock for Microbial Lipid Production

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1009
Author(s):  
Gwon Woo Park ◽  
Seongsoo Son ◽  
Myounghoon Moon ◽  
Subin Sin ◽  
Kyoungseon Min ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Response Surface Methodology ◽  
Carbon Source ◽  
Response Surface ◽  
Volatile Fatty Acids ◽  
Lipid Production ◽  
Biodiesel Production ◽  
Microbial Lipid ◽  
Initial Ph ◽  
Microbial Lipid Production

Microbial lipid production from oleaginous yeasts is a promising process for the sustainable development of the microbial biodiesel industry. However, the feedstock cost poses an economic problem for the production of microbial biodiesel. After lipid extraction, yeast biomass can be used as an organic source for microbial biodiesel production. In this study, volatile fatty acids (VFAs), produced via anaerobic digestion of a lipid-extracted yeast (LEY) residue, were utilized as a carbon source for the yeast Cryptococcus curvatus. The response surface methodology was used to determine the initial pH and inoculum volume for the optimal VFA production. The experimental result for VFA concentration was 4.51 g/L at an initial pH of 9 and an inoculation 25%. The optimization results from the response surface methodology showed that the maximal VFA concentration was 4.58 g/L at an initial pH of 8.40 and an inoculation of 39.49%. This study indicates that VFAs from LEY can be used as a carbon source for microbial biodiesel production, with the potential to significantly reduce feedstock costs.

scholarly journals Propionate Production by Bioelectrochemically-Assisted Lactate Fermentation and Simultaneous CO2 Recycling

2020 ◽  
Vol 11 ◽  
Author(s):  
Marco Isipato ◽  
Paolo Dessì ◽  
Carlos Sánchez ◽  
Simon Mills ◽  
Umer Z. Ijaz ◽  
...  
Keyword(s):  
Fossil Fuels ◽  
Volatile Fatty Acids ◽  
Community Analysis ◽  
Building Blocks ◽  
Ph Control ◽  
Microbial Community Analysis ◽  
Waste Streams ◽  
Ph Buffering ◽  
Initial Ph ◽  
Lactate Fermentation

Production of volatile fatty acids (VFAs), fundamental building blocks for the chemical industry, depends on fossil fuels but organic waste is an emerging alternative substrate. Lactate produced from sugar-containing waste streams can be further processed to VFAs. In this study, electrofermentation (EF) in a two-chamber cell is proposed to enhance propionate production via lactate fermentation. At an initial pH of 5, an applied potential of −1 V vs. Ag/AgCl favored propionate production over butyrate from 20 mM lactate (with respect to non-electrochemical control incubations), due to the pH buffering effect of the cathode electrode, with production rates up to 5.9 mM d–1 (0.44 g L–1 d–1). Microbial community analysis confirmed the enrichment of propionate-producing microorganisms, such as Tyzzerella sp. and Propionibacterium sp. Organisms commonly found in microbial electrosynthesis reactors, such as Desulfovibrio sp. and Acetobacterium sp., were also abundant at the cathode, indicating their involvement in recycling CO2 produced by lactate fermentation into acetate, as confirmed by stoichiometric calculations. Propionate was the main product of lactate fermentation at substrate concentrations up to 150 mM, with a highest production rate of 12.9 mM d–1 (0.96 g L–1 d–1) and a yield of 0.48 mol mol–1 lactate consumed. Furthermore, as high as 81% of the lactate consumed (in terms of carbon) was recovered as soluble product, highlighting the potential for EF application with high-carbon waste streams, such as cheese whey or other food wastes. In summary, EF can be applied to control lactate fermentation toward propionate production and to recycle the resulting CO2 into acetate, increasing the VFA yield and avoiding carbon emissions and addition of chemicals for pH control.

scholarly journals A Two-Stage Process for Conversion of Brewer’s Spent Grain into Volatile Fatty Acids through Acidogenic Fermentation

2021 ◽  
Vol 11 (7) ◽  
pp. 3222
Author(s):  
Eliana C. Guarda ◽  
Ana Catarina Oliveira ◽  
Sílvia Antunes ◽  
Filomena Freitas ◽  
Paula M. L. Castro ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Organic Acid ◽  
Volatile Fatty Acids ◽  
Operation Mode ◽  
Granular Sludge ◽  
Building Blocks ◽  
Organic Load ◽  
Fermentation Products ◽  
Acidogenic Fermentation ◽  
The Impact

This work is focused on the valorization of brewer’s spent grains (BSG) into volatile fatty acids (VFA) through acidogenic fermentation. VFAs are building blocks for several applications, such as bioplastics’ production. Using acid hydrolysis as pre-treatment, several batch assays were performed and the impact of organic load (OL) and pH on VFA production from BSG hydrolysate was assessed. Regardless of the condition, the produced acids were mainly butyric and acetic acids followed by propionic acid. The OL had a direct impact on the total organic acid concentration with higher concentrations at the highest OL (40 gCOD L−1). pH affected the concentration of individual organic acid, with the highest fermentation products (FP) diversity attained at pH 5.0 and OL of 40 gCOD L−1. To assess the potential application of organic acids for biopolymers (such as polyhydroxyalkanoates) production, the content in hydroxybutyrate (HB) and hydroxyvalerate (HV) monomers was estimated from the respective precursors produced at each pH and OL. The content in HV precursors increased with pH, with a maximum at pH 6.0 (ca. 16% C-mol basis). The acidogenic fermentation of BSG hydrolysate was also assessed in continuous operation, using an expanded granular sludge bed reactor (EGSB). It was shown that the BSG hydrolysate was successfully converted to VFAs without pH control, achieving higher productivities than in the batch operation mode.

The effect of extreme temperatures (70–80°C) on the effluent quality and sludge characteristics of UASB reactors

1997 ◽  
Vol 36 (6-7) ◽  
pp. 325-332 ◽  
Author(s):  
Raghida Lepistö ◽  
Jukka Rintala
Keyword(s):  
Volatile Fatty Acids ◽  
Granular Sludge ◽  
Anaerobic Sludge ◽  
Methanogenic Activity ◽  
Sludge Characteristics ◽  
Effluent Quality ◽  
Start Up ◽  
Thermomechanical Pulping ◽  
Increasing Temperature ◽  
Uasb Reactors

The study focused on the effluent quality and sludge characteristics during the start-up and operation of extreme thermophilic (70 to 80°C) upflow anaerobic sludge bed (UASB) reactors, inoculated with mesophilic and thermophilic granular sludge and fed with acetate, volatile fatty acids (VFA), and thermomechanical pulping (TMP) whitewater. Low effluent quality and long start-up periods were observed during the start-up of the 70 to 76°C, VFA-fed UASB reactors inoculated with mesophilic granulae, while better effluent quality and considerably shorter start-up periods were observed when thermophilic (55/70°C) inocula were used. With VFA feed, a significant amount of acetate was removed at 70°C and even at 80°C, while propionate removal was negligible. With TMP whitewater feed, low VFA effluent concentration was obtained at 70°C. The volatile solids (VS) and the VS/total solids (TS) content of the sludge decreased significantly during the first 2–3 months of operation when mesophilic inocula were used. The initial specific methanogenic activity (ISMA) of the extreme thermophilic sludge decreased with increasing temperature and was slightly higher on glucose than on acetate. At 70 to 80°C, various rod-like bacteria were dispersed through the granulae in either individual or in low density micro colonies surrounded with a varying degree of precipitates.

scholarly journals Wine By-Products as Raw Materials for the Production of Biopolymers and of Natural Reinforcing Fillers: A Critical Review

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 381
Author(s):  
Alessandro Nanni ◽  
Mariafederica Parisi ◽  
Martino Colonna
Keyword(s):  
Critical Review ◽  
Raw Materials ◽  
Green Revolution ◽  
Building Blocks ◽  
Poly Lactic Acid ◽  
Butylene Succinate ◽  
Reinforcing Fillers ◽  
Plastic Industry ◽  
Review Reports ◽  
By Products

The plastic industry is today facing a green revolution; however, biopolymers, produced in low amounts, expensive, and food competitive do not represent an efficient solution. The use of wine waste as second-generation feedstock for the synthesis of polymer building blocks or as reinforcing fillers could represent a solution to reduce biopolymer costs and to boost the biopolymer presence in the market. The present critical review reports the state of the art of the scientific studies concerning the use of wine by-products as substrate for the synthesis of polymer building blocks and as reinforcing fillers for polymers. The review has been mainly focused on the most used bio-based and biodegradable polymers present in the market (i.e., poly(lactic acid), poly(butylene succinate), and poly(hydroxyalkanoates)). The results present in the literature have been reviewed and elaborated in order to suggest new possibilities of development based on the chemical and physical characteristics of wine by-products.

scholarly journals Economic and Sustainability of Biodiesel Production—A Systematic Literature Review

2021 ◽  
Vol 3 (1) ◽  
pp. 19-36
Author(s):  
Tamás Mizik ◽  
Gábor Gyarmati
Keyword(s):  
Literature Review ◽  
Systematic Literature Review ◽  
Volatile Fatty Acids ◽  
First Generation ◽  
Production Costs ◽  
Raw Material ◽  
Biodiesel Production ◽  
Important Research Topic ◽  
The Social ◽  
High Production

As Earth’s fossil energy resources are limited, there is a growing need for renewable resources such as biodiesel. That is the reason why the social, economic and environmental impacts of biofuels became an important research topic in the last decade. Depleted stocks of crude oil and the significant level of environmental pollution encourage researchers and professionals to seek and find solutions. The study aims to analyze the economic and sustainability issues of biodiesel production by a systematic literature review. During this process, 53 relevant studies were analyzed out of 13,069 identified articles. Every study agrees that there are several concerns about the first-generation technology; however, further generations cannot be price-competitive at this moment due to the immature technology and high production costs. However, there are promising alternatives, such as wastewater-based microalgae with up to 70% oil content, fat, oils and grease (FOG), when production cost is below 799 USD/gallon, and municipal solid waste-volatile fatty acids technology, where the raw material is free. Proper management of the co-products (mainly glycerol) is essential, especially at the currently low petroleum prices (0.29 USD/L), which can only be handled by the biorefineries. Sustainability is sometimes translated as cost efficiency, but the complex interpretation is becoming more common. Common elements of sustainability are environmental and social, as well as economic, issues.

scholarly journals Factors influencing the adsorption and photocatalysis of direct red 80 in the presence of a TiO2: Equilibrium and kinetics modeling

2021 ◽  
pp. 174751982198996
Author(s):  
Moussa Abbas
Keyword(s):  
Elimination Rate ◽  
Threshold Value ◽  
Heterogeneous Photocatalysis ◽  
Order Kinetic ◽  
Batch Mode ◽  
Adsorption Capacities ◽  
Initial Ph ◽  
Equilibrium And Kinetics ◽  
Order Kinetic Model ◽  
Charge Point

Among the different photocatalysts, TiO2 ( Eg = 3.1 eV, zero charge point (pHpzc = 6.3), and surface = 55 m2/g) is currently the most efficient and the most studied semiconductor due to its strong photocatalytic activity, non-toxicity, and chemical stability. The elimination of DR-80 on TiO2 is studied by adsorption in batch mode and by application of heterogeneous photocatalysis onto TiO2 under UV irradiation. The effects of contact time (0–60 min), initial pH (3–11), dose of the adsorbent (0.5–3 g L−1), and DR-80 concentration (40–60 mg L−1) on the adsorption of DR-80 by TiO2 are studied for optimization of these parameters. The kinetic parameters, rate constants, and equilibrium adsorption capacities are calculated and discussed for each applied theoretical model. The adsorption of DR-80 is well described by the pseudo-first-order kinetic model. The fitting of the adsorption isotherms shows that the models of Langmuir and Temkin offering a better fit and an adsorption 64.102 mg/g at 25 °C of DR-80 are eliminated. The results showed that the photocatalytic efficiency strongly depends on the pH while the initial rate of photodegradation is proportional to the catalyst dose, and becomes almost constant above a threshold value. It was found that the photodegradation is favored at low DR-80 concentrations in accordance with the Langmuir–Hinshelwood model with the constants Kad = 6.5274 L/mg and KL–H = 0.17818 mg L−1 min. However, the adsorption is improved for high DR-80 concentrations. It is found that the degradation depends on both the temperature and the pH with a high elimination rate at high temperature. The photocatalyst TiO2 has a better activity for the degradation of DR-80, compared to some commercial catalysts that have been described in the literature.

scholarly journals Deep Eutectic Solvents Based Choline Chloride for Enzymatic Biodiesel Production from Degumming Palm Oil

2020 ◽  
Vol 32 (4) ◽  
pp. 733-738 ◽  
Author(s):  
R. Manurung ◽  
Taslim ◽  
A.G.A. Siregar
Keyword(s):  
Palm Oil ◽  
Raw Materials ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Deep Eutectic Solvents ◽  
Biodiesel Production ◽  
Chloride Salt ◽  
Enzymatic Reactions ◽  
Potential Applications ◽  
Palm Oil Biodiesel

Deep eutectic solvents (DESs) have numerous potential applications as cosolvents. In this study, use of DES as organic solvents for enzymatic biodiesel production from degumming palm oil (DPO) was investigated. Deep eutectic solvent was synthesized using choline chloride salt (ChCl) compounds with glycerol and 1,2-propanediol. Deep eutectic solvent was characterized by viscosity, density, pH and freezing values, which were tested for effectiveness by enzymatic reactions for the production of palm biodiesel with raw materials DPO. Deep eutectic solvent of ChCl and glycerol produced the highest biodiesel yield (98.98%); weight of DES was only 0.5 % of that of the oil. In addition, the use of DES maintained the activity and stability of novozym enzymes, which was assessed as the yield until the 6th usage, which was 95.07 % biodiesel yield compared with the yield without using DES. Hence, using DES, glycerol in enzymatic biodiesel production had high potentiality as an organic solvent for palm oil biodiesel production

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