Search results for "polyhydroxyalkanoate"

Recovery of polyhydroxyalkanoates (PHAs) from wastewater : a review

2020

Abstract Polyhydroxyalkanoates (PHAs) are biopolyesters accumulated as carbon and energy storage materials under unbalanced growth conditions by various microorganisms. They are one of the most promising potential substitutes for conventional non-biodegradable plastics due to their similar physicochemical properties, but most important, its biodegradability. Production cost of PHAs is still a great barrier to extend its application at industrial scale. In order to reduce that cost, research is focusing on the use of several wastes as feedstock (such as agro-industrial and municipal organic waste and wastewater) in a platform based on mixed microbial cultures. This review provides a critical…

Bioplastic recovery from wastewater: A new protocol for polyhydroxyalkanoates (PHA) extraction from mixed microbial cultures

2019

Abstract A new protocol for polyhydroxyalkanoates (PHA) extraction from mixed microbial cultures (MMCs) is proposed. PHA-accumulating capacity of the MMC was selected in a sequencing batch reactor (SBR) fed with a synthetic effluent emulating a fermented oil mill wastewater (OMW). The highest recovery yield and purity (74 ± 8% and 100 ± 5%, respectively) was obtained when using NH4-Laurate for which operating conditions of the extraction process such as temperature, concentration and contact time were optimized. Best conditions for PHA extraction from MMC turned to be: i) a pre-treatment with NaClO at 85 °C with 1 h of contact time, followed by ii) a treatment with lauric acid in a ratio ac…

Antiviral properties of silver nanoparticles against norovirus surrogates and their efficacy in coated polyhydroxyalkanoates systems

2017

Silver nanoparticles (AgNP) have strong broad-spectrum antimicrobial activity and gained increased attention for the development of AgNP based products, including medical and food applications. Initially, the efficacy of AgNP and silver nitrate (AgNO3) was evaluated for inactivating norovirus surrogates, the feline calicivirus (FCV) and the murine norovirus (MNV). These norovirus surrogates were exposed to AgNO3 and AgNP solutions for 24 h at 25 °C and then analyzed by cell-culture assays. Both AgNP and silver ions significantly decreased FCV and MNV infectivity in a dose-dependent manner between concentrations of 2.1 and 21 mg/L. Furthermore, poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (…

Poly(hydroxyalkanoate) synthase genes in pseudomonads strains, isolation and heterologous expression

2010

Transcriptome analysis of Pseudomonas mediterranea and P. corrugata plant pathogens during accumulation of medium-chain-length PHAs by glycerol bioco…

2017

Pseudomonas corrugata and P. mediterranea are soil inhabitant bacteria, generally living as endophytes on symptomless plants and bare soil, but also capable of causing plant diseases. They share a similar genome size and a high proteome similarity. P. corrugata produces many biomolecules which play an important role in bacterial cell survival and fitness. Both species produce different medium-chain-length PHAs (mcl-PHAs) from the bioconversion of glycerol to a transparent film in P. mediterranea and a sticky elastomer in P. corrugata. In this work, using RNA-seq we investigated the transcriptional profiles of both bacteria at the early stationary growth phase with glycerol as the carbon sou…

Modelling the metabolic shift of polyphosphate-accumulating organisms

2014

Enhanced biological phosphorus removal (EBPR) is one of the most important methods of phosphorus removal in municipal wastewater treatment plants, having been described by different modelling approaches. In this process, the PAOs (polyphosphate accumulating organisms) and GAOs (glycogen accumulating organisms) compete for volatile fatty acids uptake under anaerobic conditions. Recent studies have revealed that the metabolic pathways used by PAOs in order to obtain the energy and the reducing power needed for polyhydroxyalkanoates synthesis could change depending on the amount of polyphosphate stored in the cells. The model presented in this paper extends beyond previously developed metaboli…

Processing and Properties of Biopolymer/Polyhydroxyalkanoates Blends

2011

In this paper, the processability and the performance of a biodegradable polymer, Mater-Bi, and of its blends with either a sample of poly (hydroxy alkanoates) (PHA) or with bacterial biomass containing PHAs were compared. Adding PHA or directly the biomass containing it allows improving the processability of the matrix. Moreover, the mechanical behaviour of the systems was compared considering two different preparation methods, namely compression and injection moulding. The injection moulded samples show poorer mechanical performances than those of the compression moulded systems. The impact strength significantly improves when PHA is added while it reduces when bacterial biomass is used i…

Properties of Halococcus salifodinae, an Isolate from Permian Rock Salt Deposits, Compared with Halococci from Surface Waters

2013

Halococcus salifodinae BIpT DSM 8989T, an extremely halophilic archaeal isolate from an Austrian salt deposit (Bad Ischl), whose origin was dated to the Permian period, was described in 1994. Subsequently, several strains of the species have been isolated, some from similar but geographically separated salt deposits. Hcc. salifodinae may be regarded as one of the most ancient culturable species which existed already about 250 million years ago. Since its habitat probably did not change during this long period, its properties were presumably not subjected to the needs of mutational adaptation. Hcc. salifodinae and other isolates from ancient deposits would be suitable candidates for testing …

Anaerobic central metabolic pathways active during polyhydroxyalkanoate production in uncultured cluster 1Defluviicoccusenriched in activated sludge …

2009

A glycogen nonpolyphosphate-accumulating organism (GAO) enrichment culture dominated by the Alphaproteobacteria cluster 1 Defluviicoccus was investigated to determine the metabolic pathways involved in the anaerobic formation of polyhydroxyalkanoates, carbon storage polymers important for the proliferation of microorganisms in enhanced biological phosphorus removal processes. FISH-microautoradiography and post-FISH fluorescent chemical staining confirmed acetate assimilation as polyhydroxyalkanoates in cluster 1 Defluviicoccus under anaerobic conditions. Chemical inhibition of glycolysis using iodoacetate, and of isocitrate lyase by 3-nitropropionate and itaconate, indicated that carbon is …

Effect of organic loading rate on the production of Polyhydroxyalkanoates from sewage sludge

2023

The aim of this work was to study the effect of organic loading rate on the production of Polyhydroxyalkanoates (PHA) from sewage sludge. Synthesis of PHA using sewage sludge as platform was achieved in this work. Three pilot-scale selection-sequencing batch reactors (S-SBR) were used for obtaining a culture able to accumulate PHA following a strategy of aerobic dynamic feeding (ADF) at different volumetric organic-loading-rate (vOLR): 1.3, 1.8 and 0.8 g COD L-1 d-1 for S-SBR 1, S-SBR 2 and S-SBR 3, respectively. Decreasing the vOLR enhanced the general performance of the process as for organic matter removal (from 99.2% ± 0.3% in S-SBR-3 to 92 ± 2 in S-SBR-2) while the opposite trend was r…