scholarly journals Effect of pH on the Production of Volatile Fatty Acids in Dark Fermentation Process of Organic Waste

2018 ◽  
Vol 25 (2) ◽  
pp. 295-306 ◽  
Author(s):  
Justyna Grzelak ◽  
Radosław Ślęzak ◽  
Liliana Krzystek ◽  
Stanisław Ledakowicz
Keyword(s):  
Fatty Acids ◽  
Butyric Acid ◽  
Carbon Balance ◽  
Fermentation Process ◽  
Volatile Fatty Acids ◽  
Dark Fermentation ◽  
Kitchen Waste ◽  
Effect Of Ph ◽  
Batch Bioreactor ◽  
The City

Abstract The aim of this study was to investigate the effect of pH on the dark fermentation process of kitchen waste by specifying the composition of the volatile fatty acids (VFA), H2 and by drawing the carbon balance. Studies were carried out in 8 dm3 batch bioreactor in mesophilic conditions. The kitchen waste from the city of Lodz were used as a substrate. Based on the study, it was observed that most of the VFA was produced during the first two days of the process, while in the following days the production was diminished. The highest production of VFA (19.5 g/dm3) was obtained in the bioreactor, where the pH was 7 and 8. Analyzing the produced VFA it was observed that mostly the acetic and butyric acid had been produced. Most of acetic acid (over 70 %) was obtained in fermenter with pH 7 and 8. In contrast, most of the butyric acid (over 40 %) was in the bioreactor with a pH of 6. Production of H2 was in the range from 4.29 to 26.5 dm3, wherein the largest amount of H2 was created in the bioreactor with a pH of 6.

scholarly journals Pengaruh sumber karbon terhadap produksi bioplastik polihidroksialkanoat (PHA) dengan ralstonia eutropha

2018 ◽  
Vol 9 (1) ◽  
pp. 28
Author(s):  
Martha Aznury ◽  
Tjandra Setiadi ◽  
Adi Pancoro
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Carbon Source ◽  
Fermentation Process ◽  
Volatile Fatty Acids ◽  
Ralstonia Eutropha ◽  
Operating Conditions ◽  
Batch Bioreactor ◽  
Pha Production ◽  
Fructose Fermentation

Bioplastic Polyhidroxyalknoate (PHA) is a polyester type bioplastic with physicochemical properties resemble to those of polypropilen from petroleum. PHA production was investigated to determine the effect of carbon source on the fermentation process by Ralstonia eutropha. Specifically, Ralstonia eutropha was cultivated in a batch bioreactor to show the dynamics of P(3HB-co-3HV) copolymer production from glucose or fructose as C source. In adition, the effect of volatile fatty acids addition, as stimulator to the copolymer production, was also studied. The operating conditions in a 7 L bioreactor were at temperature 30 oC and pH 7.0. The concentration of carbon source glucose or fructose was 40 g/L, and after 20 hour fermentation, volatile fatty acids were added. With volatile fatty acids addition, the resulting fructose fermentation had PHA content of 32.78%, in which the HV percentage was 11.78%. Meanwhile, the fermentation of glucose, stimulated by volatile fatty acids, gave PHA as much as 20.19% with HV percentage of 8.71%. Therefore,, the Ralstonia eutropha fermentation of fructose as the carbon source gave a higher yield than glucose. Keywords: Volatil Fatty Acid, Fructose, Glucose, PHA, P(3HB-co-3HV), Ralstonia eutropha AbstrakBioplastik polihidroksialkanoat (PHA) adalah bioplastik dari kelompok poliester dengan sifat fisikokimia mirip dengan plastik polipropilen dari minyak bumi. Penelitian ini bertujuan untuk mempelajari pengaruh sumber karbon terhadap poduksi PHA yang dilakukan dengan proses fermentasi menggunakan Ralstonia eutropha. Ralstonia eutropha dikultivasi dalam bioreaktor batch untuk mempelajari dinamika produksi kopolimer P(3HB-co-3HV) dari sumber karbon glukosa atau fruktosa, serta mempelajari pengaruh sumber stimulator asam lemak volatil. Kondisi operasional fermentasi menggunakan bioreaktor 7 L adalah pada temperatur 30 oC dan pH 7. Konsentrasi sumber karbon glukosa atau fruktosa yang digunakan adalah 40 gr/L, dan setelah 20 jam fermentasi ditambahkan asam lemak volatil yang berfungsi sebagai stimulator dalam produksi P(3HB-co-3HV). Panen sel Ralstonia eutropha dilakukan setelah 60 jam. Hasil penelitian menunjukkan fermentasi Ralstonia eutropha dengan substrat fruktosa dan asam lemak volatil sebagai stimulator mempunyai kandungan PHA sebesar 32,78%, dengan kadar HV 11,78%. Pada pemberian substrat glukosa dan asam lemak volatil menunjukkan kandungan PHA sebesar 20,19%, dengan kadar HV 8.71%. Jadi fermentasi Ralstonia eutropha dengan menggunakan substrat fruktosa memberikan yield yang lebih tinggi dibandingkan menggunakan substrat glukosa.Kata Kunci: Asam lemak volatil, fruktosa, glukosa, PHA, P(3HB-co-3HV), Ralstonia eutropha

scholarly journals Acclimation of microorganisms for an efficient production of volatile fatty acids and biogas from mezcal vinasses in a dark fermentation process

2021 ◽  
Author(s):  
S. A. Díaz-Barajas ◽  
M. A. Garzón-Zúñiga ◽  
I. Moreno-Andrade ◽  
J. M. Vigueras-Cortés ◽  
B. E. Barragán-Huerta
Keyword(s):  
Fatty Acids ◽  
Organic Matter ◽  
Removal Efficiency ◽  
Fermentation Process ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Removal Rate ◽  
Organic Content ◽  
Dark Fermentation ◽  
Efficient Production

Abstract Mezcal is an alcoholic artisanal drink made from agave plants in Mexico. Its production causes the generation of wastewater called vinasses, which are highly polluting residues due to its concentration of organic matter as chemical oxygen demand (COD) (35,000–122,000 mg/L) and acidity (pH < 4). Due to their organic content, these residues can be used in dark fermentation to obtain biogas, which is rich in hydrogen. In this work, the acclimation of inoculum by means of a dark fermentation process, in the presence of toxic compounds from mezcal vinasses was studied. The strategy of increasing the initial concentration of vinasse in each treatment cycle in a SBR reactor was applied. It was possible to obtain a maximum biogas production of 984 ± 187 mL/L, from vinasses (18,367 ± 1,200 mg COD/L), with an organic matter removal efficiency of 20 ± 1%. A maximum generation of volatile fatty acids (VFA) of 980 ± 538 mg/L equivalent to a production of 74 ± 21% of the influent concentration and removal rate of organic matter of 1,125 ± 234 mg COD/L d−1 equivalent to a removal efficiency of 20 ± 4% was obtained from vinasses with a concentration of 19,648 ± 1,702 mg COD/L.

Use of organic waste for biohydrogen production and volatile fatty acids via dark fermentation and further processing to methane

2019 ◽  
Vol 44 (44) ◽  
pp. 24110-24125 ◽  
Author(s):  
Tobias Weide ◽  
Elmar Brügging ◽  
Christof Wetter ◽  
Antonio Ierardi ◽  
Marc Wichern
Keyword(s):  
Fatty Acids ◽  
Organic Waste ◽  
Volatile Fatty Acids ◽  
Dark Fermentation ◽  
Biohydrogen Production

scholarly journals Study on the correlation between volatile fatty acids and gas production in dry fermentation of kitchen waste

2018 ◽  
Vol 121 ◽  
pp. 032044 ◽  
Author(s):  
Qiangqiang Li ◽  
Yunfeng Ma ◽  
Boying Du ◽  
Qi Wang ◽  
Qiongqiong Hu ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Gas Production ◽  
Kitchen Waste ◽  
Dry Fermentation

scholarly journals Enhanced lipid production by Yarrowia lipolytica cultured with synthetic and waste-derived high-content volatile fatty acids under alkaline conditions

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Ruiling Gao ◽  
Zifu Li ◽  
Xiaoqin Zhou ◽  
Wenjun Bao ◽  
Shikun Cheng ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Propionic Acid ◽  
Yarrowia Lipolytica ◽  
Butyric Acid ◽  
Lipid Content ◽  
Volatile Fatty Acids ◽  
Lipid Production ◽  
Initial Ph ◽  
Alkaline Conditions

Abstract Background Volatile fatty acids (VFAs) can be effective and promising alternate carbon sources for microbial lipid production by a few oleaginous yeasts. However, the severe inhibitory effect of high-content (> 10 g/L) VFAs on these yeasts has impeded the production of high lipid yields and their large-scale application. Slightly acidic conditions have been commonly adopted because they have been considered favorable to oleaginous yeast cultivation. However, the acidic pH environment further aggravates this inhibition because VFAs appear largely in an undissociated form under this condition. Alkaline conditions likely alleviate the severe inhibition of high-content VFAs by significantly increasing the dissociation degree of VFAs. This hypothesis should be verified through a systematic research. Results The combined effects of high acetic acid concentrations and alkaline conditions on VFA utilization, cell growth, and lipid accumulation of Yarrowia lipolytica were systematically investigated through batch cultures of Y. lipolytica by using high concentrations (30–110 g/L) of acetic acid as a carbon source at an initial pH ranging from 6 to 10. An initial pH of 8 was determined as optimal. The highest biomass and lipid production (37.14 and 10.11 g/L) were obtained with 70 g/L acetic acid, whereas cultures with > 70 g/L acetic acid had decreased biomass and lipid yield due to excessive anion accumulation. Feasibilities on high-content propionic acid, butyric acid, and mixed VFAs were compared and evaluated. Results indicated that YX/S and YL/S of cultures on butyric acid (0.570, 0.144) were comparable with those on acetic acid (0.578, 0.160) under alkaline conditions. The performance on propionic acid was much inferior to that on other acids. Mixed VFAs were more beneficial to fast adaptation and lipid production than single types of VFA. Furthermore, cultures on food waste (FW) and fruit and vegetable waste (FVW) fermentate were carried out and lipid production was effectively improved under this alkaline condition. The highest biomass and lipid production on FW fermentate reached 14.65 g/L (YX/S: 0.414) and 3.20 g/L (YL/S: 0.091) with a lipid content of 21.86%, respectively. By comparison, the highest biomass and lipid production on FVW fermentate were 11.84 g/L (YX/S: 0.534) and 3.08 g/L (YL/S: 0.139), respectively, with a lipid content of 26.02%. Conclusions This study assumed and verified that alkaline conditions (optimal pH 8) could effectively alleviate the lethal effect of high-content VFA on Y. lipolytica and significantly improve biomass and lipid production. These results could provide a new cultivation strategy to achieve simple utilizations of high-content VFAs and increase lipid production. Feasibilities on FW and FVW-derived VFAs were evaluated, and meaningful information was provided for practical applications.

Carbon balance of major volatile fatty acids (VFAs) in recycling algal residue via a VFA-platform for reproduction of algal biomass

2019 ◽  
Vol 237 ◽  
pp. 228-234 ◽  
Author(s):  
Donghyun Kim ◽  
Sungwhan Kim ◽  
Jong-In Han ◽  
Ji-Won Yang ◽  
Yong Keun Chang ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Carbon Balance ◽  
Algal Biomass ◽  
Volatile Fatty Acids

scholarly journals Impact of Alkaline Pretreatment to Enhance Volatile Fatty Acids (VFAs) Production from Rice Husk

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Qian Fang ◽  
Sinmin Ji ◽  
Dingwu Huang ◽  
Zhouyue Huang ◽  
Zilong Huang ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Propionic Acid ◽  
Butyric Acid ◽  
Rice Husk ◽  
Volatile Fatty Acids ◽  
Alkaline Pretreatment ◽  
Rice Husks ◽  
Acid Fermentation ◽  
Study Results

This study explores the use of alkaline pretreatments to improve the hydrolyzation of rice husks to produce volatile fatty acids (VFAs). The study investigated the effects of reagent concentration and pretreatment time on protein, carbohydrates, and dissolved chemical oxygen demand (SCOD) dissolution after the pretreatment. The optimum alkaline pretreatment conditions were 0.30 g NaOH (g VS)−1, with a reaction time of 48 h. The experimental results show that when comparing the total VFA (TVFA) yields from the alkaline-pretreated risk husk with those from the untreated rice husk, over 14 d and 2 d, the maximum value reached 1237.7 and 716.0 mg·L−1 with acetic acid and propionic acid and with acetic acid and butyric acid, respectively. After the alkaline pretreatment, TVFAs increased by 72.9%; VFA accumulation grew over time. The study found that alkaline pretreatment can improve VFA yields from rice husks and transform butyric acid fermentation into propionic acid fermentation. The study results can provide guidelines to support the comprehensive utilization of rice husk and waste treatment.

scholarly journals Recovery of volatile fatty acids (VFA) from complex waste effluents using membranes

2013 ◽  
Vol 69 (3) ◽  
pp. 495-503 ◽  
Author(s):  
M.-P. Zacharof ◽  
R. W. Lovitt
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Butyric Acid ◽  
Volatile Fatty Acids ◽  
Agricultural Waste ◽  
Permeate Flux ◽  
Anaerobic Digesters ◽  
Waste Effluents

Waste effluents from anaerobic digesters of agricultural waste were treated with a range of membranes, including microfiltration and nanofiltration (NF), to concentrate volatile fatty acids (VFA). Microfiltration was applied successfully to produce sterile, particle-free solutions with a VFA concentration of 21.08 mM of acetic acid and 15.81 mM of butyric acid. These were further treated using a variety of NF membranes: NF270 (Dow Chemicals, USA), HL, DL, DK (Osmonics, USA) and LF10 (Nitto Denko, Japan), achieving retention ratios of up to 75%, and giving retentates of up to 53.94 mM of acetate and 28.38 mM of butyrate. DK and NF270 membranes were identified as the best candidates for VFA separation and concentration from these multicomponent effluents, both in terms of retention and permeate flux. When the effluents are adjusted to alkali conditions, the highest productivity, retention and flux were achieved at pH 7. At higher pH there was a significant reduction in flux.

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