scholarly journals Production of a newly discovered PHA family member with an isobutyrate-fed enrichment culture

2022 ◽  
Author(s):  
Chris M. Vermeer ◽  
Larissa J. Bons ◽  
Robbert Kleerebezem
Keyword(s):  
Family Member ◽  
Metabolic Pathways ◽  
Volatile Fatty Acids ◽  
Anaerobic Fermentation ◽  
Enrichment Culture ◽  
Dry Weight ◽  
Chain Elongation ◽  
Structural Isomer ◽  
Distinct Character ◽  
Pha Production

Abstract Using microbial enrichment cultures for the production of waste-derived polyhydroxyalkanoates (PHAs) is a promising technology to recover secondary resources. Volatile fatty acids (VFAs) form the preferred substrate for PHA production. Isobutyrate is a VFA appearing in multiple waste valorization routes, such as anaerobic fermentation, chain elongation, and microbial electrosynthesis, but has never been assessed individually on its PHA production potential. This research investigates isobutyrate as sole carbon source for a microbial enrichment culture in comparison to its structural isomer butyrate. The results reveal that the enrichment of isobutyrate has a very distinct character regarding microbial community development, PHA productivity, and even PHA composition. Although butyrate is a superior substrate in almost every aspect, this research shows that isobutyrate-rich waste streams have a noteworthy PHA-producing potential. The main finding is that the dominant microorganism, a Comamonas sp., is linked to the production of a unique PHA family member, poly(3-hydroxyisobutyrate) (PHiB), up to 37% of the cell dry weight. This is the first scientific report identifying microbial PHiB production, demonstrating that mixed microbial communities can be a powerful tool for discovery of new metabolic pathways and new types of polymers. Key points • PHiB production is a successful storage strategy in an isobutyrate-fed SBR • Isomers isobutyrate and butyrate reveal a very distinct PHA production behavior • Enrichments can be a tool for discovery of new metabolic pathways and polymers Graphical abstract

Production of polyhydroxyalkanoates by glycogen accumulating organisms treating a paper mill wastewater

2008 ◽  
Vol 58 (2) ◽  
pp. 323-330 ◽  
Author(s):  
Simon Bengtsson ◽  
Alan Werker ◽  
Thomas Welander
Keyword(s):  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Dry Weight ◽  
Paper Mill ◽  
Batch Experiments ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Pha Production ◽  
Paper Mill Wastewater ◽  
Enrichment Strategy

A process for production of polyhydroxyalkanoates (PHA) by activated sludge treating a paper mill wastewater was investigated. The applied strategy was to select for glycogen accumulating organisms (GAOs) by alternating anaerobic/aerobic conditions. Acidogenic fermentation was used as pretreatment to convert various organic compounds to volatile fatty acids which are preferable substrates for PHA production. Enrichment resulted in a culture dominated by GAOs related to Defluviicoccus vanus (56%) and Candidatus Competibacter phosphatis (22%). Optimization of PHA accumulation by the enriched GAO culture was performed through batch experiments. Accumulation of PHA under anaerobic conditions was limited by the intracellular glycogen stored. Under aerobic conditions significant glycogen production (to 25% of sludge dry weight) was observed alongside PHA accumulation (to 22% of sludge dry weight). By applying a subsequent anaerobic period after an initial aerobic, the produced glycogen could be utilized for further PHA accumulation and by this strategy PHA content was increased to 42% of sludge dry weight. The PHA yield over the entire process was 0.10 kg per kg of influent COD treated which is similar to what has been achieved with a process applying feast/famine enrichment strategy with the same wastewater.

Production of polyhydroxyalkanoate (PHA) by Ralstonia eutropha JMP 134 with volatile fatty acids from palm oil mill effluent as precursors

2015 ◽  
Vol 72 (11) ◽  
pp. 1889-1895 ◽  
Author(s):  
Tjandra Setiadi ◽  
Martha Aznury ◽  
Azis Trianto ◽  
Adi Pancoro
Keyword(s):  
Fatty Acids ◽  
Palm Oil ◽  
Volatile Fatty Acids ◽  
Ralstonia Eutropha ◽  
Anaerobic Fermentation ◽  
Palm Oil Mill Effluent ◽  
Fed Batch ◽  
Batch Mode ◽  
Pha Production ◽  
Palm Oil Mill

The highest volatile fatty acids (VFAs) concentration from palm oil mill effluent (POME) treated by anaerobic fermentation was achieved for a 1-day process when the main acids used were acetic, propionic and butyric acids. Polyhydroxyalkanoate (PHA) production with VFAs from POME as precursors in the fed-batch mode has advantages over batch mode, both in terms of its productivity and 3HV (3-hydroxyvalerate) composition in the produced polymer. With the fed batch, the productivity increased to 343% and contained more 3HV than those of the batch. The structures of the PHA were identified by different methods and they supported each other; the resulting products consisted of functional groups of 3HB (3-hydroxybutyrate) and 3HV.

Unravelling a microbial synergy to boost caproate production via carboxylates chain elongation with ethanol

2019 ◽  
Vol 26 (2) ◽  
pp. 63-71
Author(s):  
Ling Leng ◽  
Ying Wang ◽  
Peixian Yang ◽  
Takashi Narihiro ◽  
Masaru Konishi Nobu ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Microbial Consortia ◽  
Chain Elongation ◽  
Desulfovibrio Vulgaris ◽  
Rrna Gene ◽  
Selective Enrichment ◽  
Microbial Network ◽  
Cost Efficient ◽  
Rrna Gene Sequencing

Chain elongation of volatile fatty acids for medium chain fatty acids production (e.g. caproate) is an attractive approach to treat wastewater anaerobically and recover resource simultaneously. Undefined microbial consortia can be tailored to achieve chain elongation process with selective enrichment from anaerobic digestion sludge, which has advantages over pure culture approach for cost-efficient application. Whilst the metabolic pathway of the dominant caproate producer, Clostridium kluyveri, has been annotated, the role of other coexisting abundant microbiomes remained unclear. To this end, an ethanol-acetate fermentation inoculated with fresh digestion sludge at optimal conditions was conducted. Also, physiological study, thermodynamics and 16 S rRNA gene sequencing to elucidate the biological process by linking the system performance and dominant microbiomes were integrated. Results revealed a possible synergistic network in which C. kluyveri and three co-dominant species, Desulfovibrio vulgaris, Fusobacterium varium and Acetoanaerobium sticklandii coexisted. D. vulgaris and A. sticklandii (F. varium) were likely to boost the carboxylates chain elongation by stimulating ethanol oxidation and butyrate production through a syntrophic partnership with hydrogen (H2) serving as an electron messenger. This study unveils a synergistic microbial network to boost caproate production in mixed culture carboxylates chain elongation.

scholarly journals A Comprehensive Understanding of Electro-Fermentation

Fermentation ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 92 ◽  
Author(s):  
Drishti Dinesh Bhagchandanii ◽  
Rishi Pramod Babu ◽  
Jayesh M. Sonawane ◽  
Namita Khanna ◽  
Soumya Pandit ◽  
...  
Keyword(s):  
Metabolic Pathways ◽  
Biomass Yield ◽  
Carbon Chain ◽  
Industrial Applications ◽  
Chain Elongation ◽  
Comprehensive Understanding ◽  
Specific Product ◽  
Microbial Strains ◽  
Metabolic Reactions ◽  
Almost All

Electro-fermentation (EF) is an upcoming technology that can control the metabolism of exoelectrogenic bacteria (i.e., bacteria that transfer electrons using an extracellular mechanism). The fermenter consists of electrodes that act as sink and source for the production and movement of electrons and protons, thus generating electricity and producing valuable products. The conventional process of fermentation has several drawbacks that restrict their application and economic viability. Additionally, metabolic reactions taking place in traditional fermenters are often redox imbalanced. Almost all metabolic pathways and microbial strains have been studied, and EF can electrochemically control this. The process of EF can be used to optimize metabolic processes taking place in the fermenter by controlling the redox and pH imbalances and by stimulating carbon chain elongation or breakdown to improve the overall biomass yield and support the production of a specific product. This review briefly discusses microbe-electrode interactions, electro-fermenter designs, mixed-culture EF, and pure culture EF in industrial applications, electro methanogenesis, and the various products that could be hence generated using this process.

Sludge accumulation and methanogenic activity in an anaerobic lagoon

2000 ◽  
Vol 42 (10-11) ◽  
pp. 247-255 ◽  
Author(s):  
J. Paing ◽  
B. Picot ◽  
J. P. Sambuco ◽  
A. Rambaud
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Anaerobic Degradation ◽  
Volatile Fatty Acids ◽  
Anaerobic Fermentation ◽  
Methanogenic Activity ◽  
Start Up ◽  
Anaerobic Lagoon ◽  
Methane Production Rate ◽  
Sludge Accumulation

Sludge accumulation and the characteristics of anaerobic digestion in sludge had been investigated in a primary anaerobic lagoon. Methanogenic potential of sludge was evaluated by an anaerobic digestion test which measured the methane production rate. Sludge was sampled at several points in the lagoon to determine spatial variations and with a monthly frequency from the start-up of the lagoon to observe the development of anaerobic degradation. Maximum amounts of sludge accumulated near the inlet. The mean methane production of sludge was 2.9 ml gVS–1 d–1. Sludge near the outlet presented a greater methanogenic activity and a lesser concentration of volatile fatty acids than near the inlet. The different stages of anaerobic degradation were spatially separated, acidogenesis near the inlet and methanogenesis near the outlet. This staged distribution seemed to increase efficiency of anaerobic fermentation compared with septic tanks. Methane release at the surface of the lagoon was estimated to be very heterogeneous with a mean of 25 l m–2 d–1. The development of performance and sludge characteristics showed the rapid beginning of methanogenesis, three months after the start-up of the anaerobic lagoon. Considering the volume of accumulated sludge, it could however be expected that methanogenic activity would further increase.

Studies on the production of volatile fatty acids from grass by rumen liquor in an artificial rumen: II. The volatile fatty acid production from dried grass

1957 ◽  
Vol 49 (2) ◽  
pp. 171-179 ◽  
Author(s):  
A. John ◽  
G. Barnett ◽  
R. L. Reid
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Propionic Acid ◽  
Metabolic Pathways ◽  
Volatile Fatty Acid ◽  
Volatile Fatty Acids ◽  
Water Soluble ◽  
Fatty Acid Production ◽  
Growing Seasons ◽  
Titration Curves

1. A study has been made of the production of volatile fatty acids obtainable from dried grass and its gross water-soluble and water-insoluble separates, in the artificial rumen, over two growing seasons.2. In contradistinction to fresh grass, the dried grass gives a consistent production of acetic acid proportionately greater than propionic acid, at all stages of maturity, but when aqueous extracts of the dried grass, and the resultant extracted grass, respectively, are examined separately in the artificial rumen, it is found that the former yield preponderating amounts of acetic acid while the latter give amounts of propionic acid equal to, or exceeding, the corresponding productions of acetic acid.3. An examination of the titration curves for the total acids obtained from the dried grass, extracted grass and grass extract runs, indicates an approach to an incomplete relationship between the residual carbohydrate in the extracted grass and cellulose, while the grass extract reveals itself as the chief source of acetic acid in the whole dried grass, the acid being formed very speedily at the start of the run.4. The suggested sources and some of the possible metabolic pathways involved in the formation of v.f.a. from grass are discussed in the text.

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