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.

Influence of Inoculum to Substrate Ratio on Solid Acidogenic Digestion with Pig Manure and Maize Straw

2012 ◽  
Vol 518-523 ◽  
pp. 223-228
Author(s):  
Lei Zhang ◽  
Lian Zhu Du ◽  
Wen Wen Cui ◽  
Ke Qiang Zhang
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Volatile Fatty Acids ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Threshold Concentration ◽  
Pig Manure ◽  
Fermentation Products ◽  
Substrate Ratio ◽  
The Impact

A laboratory-scale study adopting mixture of manure and straw as substrate was carried out to elucidate the impact of inoculum to substrate ratio(ISR) on hydrolysis and acidification digestion with methanogenic effluent recycling. The chemical oxygen demand(COD), pH, and volatile fatty acids (VFAs) concentration were periodically analyzed in order to completely understand the digestion processing. In addition, ammonia-nitrogen was also monitored. The results showed that acetic acid was dominant in fermentation products of different ISRs and the percentage of acetic acid in total volatile fatty acids (TVFAs) increased with the increase of ISR, and acetic acid accounted to 68.74%, 72.02%, 75.89% and 86.65% of TVFAs when ISR were 15%, 25%, 35% and 50%. Propionic acid accounted for 6.68%, 5.92%, 5.54% and 2.67% of TVFAs produced, and the concentration was less than 0.60 g/L. The possible inhibition by free ammonia was null since the values were far below the threshold concentration reported in other literatures, but the potential inhibition maybe happen after long-term recycling of methanogenic effluent.

scholarly journals Rapid Two Stage Anaerobic Digestion of Nejayote through Microaeration and Direct Interspecies Electron Transfer

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1614
Author(s):  
David Valero ◽  
Carlos Rico ◽  
Raul Tapia-Tussell ◽  
Liliana Alzate-Gaviria
Keyword(s):  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Volatile Fatty Acids ◽  
Uasb Reactor ◽  
Organic Load ◽  
Great Abundance ◽  
Conductive Material ◽  
Direct Interspecies Electron Transfer ◽  
Interspecies Electron Transfer ◽  
Granulated Activated Carbon

Corn is one of the main food products in Mexico. The elaboration of corn-derived products generates wastewater with a high organic load (nejayote). Anaerobic digestion is an indicated treatment for wastewater with high organic loads. The results of this study show that the application of microaeration in the hydrolysis-fermentative reactor increased the percentage of volatile fatty acids (VFA) available in the medium by 62%. The addition of a conductive material, such as granulated activated carbon (GAC), promotes DIET (Direct interspecies electrons transfer) in the methanogenic UASB reactor increasing the methane yield by 55%. Likewise, a great diversity of exoelectrogenic bacteria, with the ability to donate electrons DIET mechanisms, were developed in the GAC biofilm, though interestingly, Peptoclostridium and Clostridium (17.3% and 12.75%, respectively) were detected with a great abundance in the GAC biofilm. Peptoclostridium has not been previously reported as a participant in DIET process.

Salinity induced acidogenic fermentation of food waste regulates biohydrogen production and volatile fatty acids profile

Fuel ◽  
2020 ◽  
Vol 276 ◽  
pp. 117794 ◽  
Author(s):  
Omprakash Sarkar ◽  
John Kiran Katari ◽  
Sulogna Chatterjee ◽  
S. Venkata Mohan
Keyword(s):  
Fatty Acids ◽  
Food Waste ◽  
Volatile Fatty Acids ◽  
Biohydrogen Production ◽  
Fatty Acids Profile ◽  
Acidogenic Fermentation

Sites of organic acid production and absorption in gastrointestinal tract of the pig

1975 ◽  
Vol 228 (2) ◽  
pp. 454-460 ◽  
Author(s):  
RA Argenzio ◽  
M Southworth
Keyword(s):  
Fatty Acids ◽  
Gastric Mucosa ◽  
Organic Acid ◽  
Intestinal Mucosa ◽  
Volatile Fatty Acids ◽  
Control Diet ◽  
Organic Acid Production ◽  
Rumen Epithelium ◽  
High Concentrations ◽  
Digesta Passage

The relationship between diet, pH, and microbial digestion of carbohydrate was examined in 24 pigs fed either a conventional or a low-protein, high-cellulose experimental diet and sacrificed 2, 4, 8, or 12 h after a meal. In animals fed the control diet contents of the cranial half of the stomach demonstrated marked, cyclic fluctuations in pH and high concentrations of organic acids. Contents of the caudal (glandular) half were lower in both pH and organic acid concentration. Despite concentrations of volatile fatty acids (VFAs) as high as 250 meq/liter in the large intestine, the pH remained relatively neutral. The VFA levels remained relatively constant throughout the length of the colon. The VFA transport across isolated gastric and large intestinal mucosa also was examined. All four types of gastric mucosa absorbed and transported VFA at substantial rates. Mucosa of pig cecum and colon transported VFA at much greater rates than gastric mucosa and greater rates than previously determined in equine large intestinal mucosa or even bovine rumen epithelium. Comparison with results of earlier studies in the pony suggested that the higher concentration of VFA in the large intestinal contents of pigs was due to the more rapid rate of digesta passage rather than to less efficient absorption of fatty acids.

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.

Sign in / Sign up

Export Citation Format

Share Document