Polyhydroxyalkanoate (PHA) production by a mixed microbial culture using sugar molasses: Effect of the influent substrate concentration on culture selection

Albuquerque, Maria G.E.; Torres, Cristiana A.V.; Reis, Maria A.M.

doi:10.1016/j.watres.2010.03.021

Cited by 274 publications

(185 citation statements)

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“…PHA accumulation (stage 3) took place in a batch reactor inoculated with sludge from the culture-enrichment SBR and fed with clarified fermented molasses. The SBR was inoculated with a PHA-accumulating mixed culture acclimatized to the fermented molasses feedstock (Albuquerque et al, 2010a).…”

Section: Methodsmentioning

confidence: 99%

“…A SBR (working volume of 800 ml) was operated using the conditions reported in Albuquerque et al, 2010a: 10-day SRT, 1-day hydraulic retention time (HRT), 12 h cycle length, organic loading rate of 90 Cmmol VFA l À 1 d À 1 . The SBR 12-h cycles consisted of four discrete periods: fill (5 min); aerobiosis (FF) (11 h); settling (45 min); and draw (10 min).…”

Section: Culture Selection In Sbrmentioning

confidence: 99%

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Link between microbial composition and carbon substrate-uptake preferences in a PHA-storing community

et al. 2012

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The microbial community of a fermented molasses-fed sequencing batch reactor (SBR) operated under feast and famine conditions for production of polyhydroxyalkanoates (PHAs) was identified and quantified through a 16 S rRNA gene clone library and fluorescence in situ hybridization (FISH). The microbial enrichment was found to be composed of PHA-storing populations (84% of the microbial community), comprising members of the genera Azoarcus, Thauera and Paracoccus. The dominant PHA-storing populations ensured the high functional stability of the system (characterized by high PHA-storage efficiency, up to 60% PHA content). The fermented molasses contained primarily acetate, propionate, butyrate and valerate. The substrate preferences were determined by microautoradiography-FISH and differences in the substrate-uptake capabilities for the various probe-defined populations were found. The results showed that in the presence of multiple substrates, microbial populations specialized in different substrates were selected, thereby co-existing in the SBR by adapting to different niches. Azoarcus and Thauera, primarily consumed acetate and butyrate, respectively. Paracoccus consumed a broader range of substrates and had a higher cell-specific substrate uptake. The relative species composition and their substrate specialization were reflected in the substrate removal rates of different volatile fatty acids in the SBR reactor.

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Section: Methodsmentioning

confidence: 99%

Section: Culture Selection In Sbrmentioning

confidence: 99%

Link between microbial composition and carbon substrate-uptake preferences in a PHA-storing community

et al. 2012

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“…To reduce the production cost of PHA and allow broad application, various researchers investigated the use of open microbial communities and waste organic carbon as substrate (Albuquerque et al, 2010;Bengtsson et al, 2008;Coats et al, 2007;Dionisi et al, 2005;Jiang et al, 2012). The process for non-axenic PHA production from organic waste comprises three steps: (1) acidogenic fermentation of the waste stream, (2) enrichment of a PHA-producing culture, and (3) production of the PHA (Dionisi et al, 2004;Serafim et al, 2008).…”

Section: -Or Recombinantmentioning

confidence: 99%

“…Once a stable culture is obtained, the SBR will be operated as a biomass production step and the excess sludge used in step 3: maximization of the PHA content of the biomass in a (nitrogen-limited) fed-batch reactor (Johnson et al, 2009a). Biomass with PHA contents of 70-80 wt% has thus been produced from fermented waste streams like molasses and paper or food industry effluents (Albuquerque et al, 2010;Jiang et al, 2012;Tamis et al, 2014). The highest PHA contents reported for microbial enrichment cultures are around 90 wt% and were obtained using sole acetate or lactate as substrate (Jiang et al, 2011b;Johnson et al, 2009a).…”

Section: -Or Recombinantmentioning

confidence: 99%

Combining the enrichment and accumulation step in non-axenic PHA production: Cultivation of Plasticicumulans acidivorans at high volume exchange ratios

Marang

Loosdrecht

Kleerebezem

2016

Journal of Biotechnology

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“…It is known that the PHA performance of a microbial population selected using waste feedstocks is influenced by the VFA composition (Duque et al 2014) and the concentration of VFA feeding the SBR (Albuquerque et al 2010). However, the selective pressure inside an SBR reactor exhibited being strong even in the presence of multiple substrates.…”

Section: Pha Synthesismentioning

confidence: 99%

Composition of mixed culture PHA biopolymers and implications for downstream processing

Montano-Herrera¹

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Polyhydroxyalkanoates (PHAs) are biopolymers synthesised and accumulated by most bacteria for carbon and energy storage. They have properties and applications comparable to petrochemical thermoplastics. Although PHAs are produced at high yields using pure biological cultures, the use of mixed cultures can significantly reduce the production costs and make use of waste streams to produce environmentally sustainable materials. In order to produce mixed culture PHAs of relevance for broader industry applications it is necessary to develop the ability to tailor polymers with diversified mechanical properties through understanding and controlling the monomer composition and compositional distribution.Diverse and complex PHA polymer structures have been achieved in mixed microbial cultures using time-based feeding strategies. However, PHA monomer composition and compositional distribution in PHA random and blocky copolymers are sensitive to substrate feeding history, making more complex the prediction of final PHA content and composition.In this sense, a better understanding of the changing cell physiologies that develop in response to different feeding strategies and substrates is necessary to design optimised feeding strategies and process control algorithms for PHA production.This thesis presents for the first time a comprehensive flux characterisation of monomer development during mixed culture PHA accumulation concurrent with biomass growth using Metabolic Flux Analysis (MFA). A dynamic trend in active biomass growth and in polymer composition was observed and was consistent over replicate accumulations. Monomer (3-hydroxybutyrate and 3-hydroxyvalerate) incorporation into poly(3-hydroxybutyate-co-3-hydroxyvalerate) copolymers in a pilot scale production system was evaluated based on published models that describe polymer production during PHA accumulation. However, it was found that these existing models could not describe the fluctuations in the proportion of Additionally, thermal degradation of mixed culture PHAs during melt processing was assessed by Near-Infrared (NIR) spectroscopy coupled to Multivariate Data Analysis. It was shown that, with correct pretreatment, a copolymeric product that was much more stable to extrusion processing than commercially available PHA was produced.Overall, this thesis explores both the fundamental and applied aspects of PHA production by mixed microbial cultures with concurrent active biomass growth. The use of computational iii tools to explore and help understand the underlying metabolic processes was explored.Polymer composition seems to follow a very complex regulation processes which can be described through the incorporation of more detailed reactions in current metabolic models.Furthermore, this thesis gives further insight into the fundamental properties of the materials produced and an assessment of their potential for degradation during processing.iv

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Polyhydroxyalkanoate (PHA) production by a mixed microbial culture using sugar molasses: Effect of the influent substrate concentration on culture selection

Cited by 274 publications

References 32 publications

Link between microbial composition and carbon substrate-uptake preferences in a PHA-storing community

Link between microbial composition and carbon substrate-uptake preferences in a PHA-storing community

Combining the enrichment and accumulation step in non-axenic PHA production: Cultivation of Plasticicumulans acidivorans at high volume exchange ratios

Composition of mixed culture PHA biopolymers and implications for downstream processing

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