Volatile fatty acids production during mixed culture fermentation – The impact of substrate complexity and pH

Jankowska, Ewelina; Chwiałkowska, Joanna; Stodolny, Mikołaj; Oleśkowicz-Popiel, Piotr

doi:10.1016/j.cej.2017.06.021

Cited by 173 publications

(89 citation statements)

References 51 publications

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“…In this sense, longer VFAs chains are converted into acetate and hydrogen through the ß‐oxidation pathway. This VFA also was found to be among the most abundant products in other studies using different substrates such as wasted activated sludge, maize silage and whey . These two VFAs accounted for ≤50% of the VFAs obtained in R1 and R2.…”

Section: Resultssupporting

confidence: 57%

Semicontinuous anaerobic digestion of protease pretreated Chlorella biomass for volatile fatty acids production

Magdalena

Llamas

Tomás‐Pejó

et al. 2019

J of Chemical Tech & Biotech

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BACKGROUND Anaerobic digestion (AD) could be designed as a source of volatile fatty acids (VFAs). However, acidogenesis optimization for novel substrates such as Chlorella vulgaris biomass needs to be investigated considering parameters such as temperature (T), organic loading rate (OLR), hydraulic retention time (HRT) and the adaptation of the sludge to temperature and substrate. RESULTS The best organic matter conversion into VFAs (CODVFA/CODin; COD, chemical oxygen demand) was achieved with HRT = 8 d, adapted anaerobic sludge (AAS) and OLR = 1.5 gCOD L−1 d−1 (CODVFA/CODin = 39.8 ± 1.0% and productivity VFA = 0.5 ± 0.1 g L−1 d−1). Acetic and butyric acids represented 50% of the total VFAs. The microbiota related to acidogenesis and acetogenesis (Firmicutes 55% of the operational taxonomic units in R5) and the low archaeal population resulted in VFA accumulation at 25 °C. CONCLUSIONS The use of low HRT and temperatures promoted VFAs production especially when AAS was employed. Microbial communities were strikingly different to the ones often found in AD targeted at biogas production. The relevance of the Firmicutes phylum (≤55% in R3 and R5) and euryarchaeota absence at 25 °C contributed to VFA accumulation. The use of AAS reported an increase in Actinobacteria species. © 2019 Society of Chemical Industry

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Section: Resultssupporting

confidence: 57%

Semicontinuous anaerobic digestion of protease pretreated Chlorella biomass for volatile fatty acids production

Magdalena

Llamas

Tomás‐Pejó

et al. 2019

J of Chemical Tech & Biotech

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“…In the present study, the rapid shift of dominated phylum from Proteobacteria to Firmicutes within 1 days of ensiling was attributed to the low pH in Napier grass silage. Jankowska, Chwialkowska, Stodolny, and Oleskowicz-Popiel (2017) Clostridia are known to be particularly sensitive to water availability, and they require very wet conditions for the proliferation. Jankowska, Chwialkowska, Stodolny, and Oleskowicz-Popiel (2017) Clostridia are known to be particularly sensitive to water availability, and they require very wet conditions for the proliferation.…”

Section: Taxonomic Classification Of the Microbial Communitiesmentioning

confidence: 99%

Microbial community dynamics and their contributions to organic acid production during the early stage of the ensiling of Napier grass (Pennisetum purpureum)

Yuan

Dong

et al. 2019

Grass and Forage Science

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The study aimed to disclose the microbial community dynamics and their contributions to organic acid production during the ensiling of Napier grass. Napier grass was harvested at the vegetative growth phase and ensiled for 30 days. Three silos were opened after 1, 2, 3, 5, 7, 14, and 30 days of ensiling respectively. The intensive fermentation was observed during the initial stage of ensiling, indicated by lower pH (<4.0) on d 2 of ensiling. Lactic acid (LA) was the primary fermentation product, although acetic acid (AA) concentration rapidly increased and LA/AA concentration gradually decreased after 3 days of ensiling. The ethanol concentration was already 11.8 g/kg DM on d 1 of ensiling and then remained stable until the end of ensiling. Lactococcus was the predominant genus during the initial 2 days of ensiling, and then, it was gradually replaced by Lactobacillus. The increase in ammonia nitrogen and butyric acid concentration after 7 days of ensiling was attributed to the growth of Clostridia, which is favored by the high moisture concentration in the Napier grass. The natural ensiling of Napier grass displayed LA‐type fermentation and was dominated by the fermentation of Lactobacillus and Lactococcus. Lactobacillus is mainly responsible for the LA production during the ensiling of Napier grass.

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“…Acidogens work better at pH 5 while pH 7–8 is optimum for methanogens performance . Moreover, acidogenic metabolic pathways are affected by digestion pH . Likewise, temperature, another easily tunable operational parameter, affects the growth and enzymatic activities of the anaerobic microbiome .…”

Section: Introductionmentioning

confidence: 99%

Volatile fatty acids production from protease pretreated Chlorella biomass via anaerobic digestion

Magdalena

Tomás‐Pejó

Ballesteros

et al. 2018

Biotechnology Progress

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Volatile fatty acids (VFAs) produced via anaerobic digestion (AD) are regarded as a low cost production process of building blocks of interest for the chemical industry. In this study, VFAs and methane production were assessed in batch reactors at different temperature ranges (psychrophilic 25°C, mesophilic 35°C, thermophilic 50°C) and different pH values (5.5 and 7.5) using protease pretreated Chlorella sp. biomass as substrate. Acetic acid and propionic acid were the most abundant products (up to 73% of the total VFAs) during the first days independently of the conditions. VFAs concentration decreased over time as methane was produced after a lag phase of 7–10 days. Results showed that best conditions for VFAs production were mesophilic temperature ranges (35°C) at neutral initial pH values (7.5), and psychrophilic temperature ranges (25°C) at low initial pH values (5.5) which resulted in a conversion of the initial COD into VFAs of 48%, respectively. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1363–1369, 2018

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Volatile fatty acids production during mixed culture fermentation – The impact of substrate complexity and pH

Cited by 173 publications

References 51 publications

Semicontinuous anaerobic digestion of protease pretreated Chlorella biomass for volatile fatty acids production

Semicontinuous anaerobic digestion of protease pretreated Chlorella biomass for volatile fatty acids production

Microbial community dynamics and their contributions to organic acid production during the early stage of the ensiling of Napier grass (Pennisetum purpureum)

Volatile fatty acids production from protease pretreated Chlorella biomass via anaerobic digestion

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