Просмотр исходного текста страницы Methane-Production-Digestion-Waste-Sludge-Methane-Hydrolysis-Rate-f

This work systematically investigated the effect of PHA levels of WAS on anaerobic methane production, using both experimental and mathematical modeling approaches. Biochemical methane potential tests showed that methane production increased with increased PHA levels in WAS. Model-based analysis suggested that the PHA-based method enhanced methane production by improving biochemical methane potential of WAS, with the highest enhancement being around 40% (from 192 to 274 L CH4/kg VS added; VS: volatile solid) when the PHA levels increased from 21 to 143 mg/g VS. In contrast, the hydrolysis rate (approximately 0. 10 d(-1)) was not significantly affected by the PHA levels. Economic analysis suggested that the PHA-based method could save $1/PE/y (PE: population equivalent) in a typical wastewater treatment plant (WWTP).<br /><br /> The PHA-based method can be easily integrated into the current WWTP to enhance methane production, thereby providing a strong support to the on-going paradigm shift in wastewater management from pollutant Unusual poly(3-hydroxyalkanoate) (PHA) biosynthesis behavior of Pseudomonas putida Bet001 and Delftia tsuruhatensis Bet002 isolated from palm oil mill Pseudomonas putida Bet001 and Delftia tsuruhatensis Bet002, isolated from palm oil mill effluent, accumulated poly(3-hydroxyalkanoates) (PHAs) when grown on aliphatic fatty acids, sugars, and glycerol. The substrates were supplied at 20:1 C/N mole ratio. Among C-even n-alkanoic acids, myristic acid gave the highest PHA content 26 and 28 wt% in P. &nbsp;putida and D. &nbsp;tsuruhatensis, respectively. Among C-odd n-alkanoic acids, undecanoic gave the highest PHA content at 40 wt% in P. &nbsp;putida and 46 wt% in D.<br /><br /> &nbsp;tsuruhatensis on pentadecanoic acid. Sugar and glycerol gave &lt;10 wt% of PHA content for both bacteria. Interestingly, D. &nbsp;tsuruhatensis accumulated both short- and medium-chain length PHA when supplied with n-alkanoic acids ranging from octanoic to lauric, sucrose, and glycerol with 3-hydroxybutyrate as the major monomer unit. In P. &nbsp;putida, the major hydroxyalkanoates unit was 3-hydroxyoctanoate and 3-hydroxydecanoate when grown on C-even acids. Conversely, 3-hydroxyheptanoate, 3-hydrxoynonanoate, and 3-hydroxyundecanoate were accumulated with C-odd acids.<br /><br /> Weight-averaged molecular weight (Mw ) was in the range of 53-81 kDa and 107-415 kDa for P. &nbsp;putida and D. tsuruhatensis, respectively. Calorimetric analyses indicated that both bacteria synthesized semicrystalline polymer with good thermal stability with degradation temperature (Td ) ranging from 178 to 282&nbsp;°C. Disruption of β-oxidation pathway in Pseudomonas putida KT2442 to produce new functionalized PHAs with thioester groups. Ramiro de Maeztu 9, 28040 Madrid, Spain. This work describes the generation of novel PHAs (named PHACOS) with a new monomer composition containing thioester groups in the side chain, which confers new properties and made them suitable for chemical modifications after their biosynthesis.<br /><br /> We have analyzed the PHACOS production abilities of the wild-type strain Pseudomonas putida KT2442 vs. its derived strain P. putida KT42FadB, mutated in the fadB gene from the central metabolic β-oxidation pathway involved in the synthesis of medium-chain-length PHA (mcl-PHA). [http://www.allinno.com/news/promotion/150.html RARECHEM AL BO 0910] based on one- or two-stage cultures have been tested resulting in PHACOS with different monomer composition. Using decanoic acid as inducer of the growth and polymer synthesis and 6-acetylthiohexanoic acid as PHA precursor in a two-stage strategy, the maximum yield was obtained by culturing the strain KT42FadB. Nuclear magnetic resonance and gas chromatography coupled to mass spectrometry showed that polymers obtained from the wild-type and KT42FadB strains, included 6-acetylthio-3-hydroxyhexanoic acid (OH-6ATH) and the shorter derivative 4-acetylthio-3-hydroxybutanoic acid (OH-4ATB) in their composition, although in different ratios. While the polymer obtained from KT42FadB strain contained mainly OH-6ATH monomer units, mcl-PHA produced by the wild-type strain contained OH-6ATH and OH-4ATB.<br /><br /> Furthermore, polyesters showed differences in the OH-alkyl derivates moiety. The strain KT42FadB overproduced PHACOS when compared to the production rate of the control strain in one- and two-stage cultures. Thermal properties obtained by differential scanning calorimetry indicated that both polymers have different glass transition temperatures related to their Microbial degradation of low-density polyethylene and synthesis of We have characterized the ability of eight bacterial strains to utilize powdered low-density polyethylene (LDPE) plastic (untreated and without any additives) as a sole carbon source. Cell mass production on LDPE-containing medium after 21 days of incubation varied between 083 ± 015 g/L cell dry mass (cdm) for Micrococcus luteus IRN20 and 09 ± 036 g/L for Cupriavidus necator H16. The percent decrease in LDPE mass ranged from 18% ± 02% for M. luteus IRN20 to 33% ± 1% for [https://en.wikipedia.org/wiki/FDCA Furane-alpha] . necator H16.<br /><br /> Linear alkane hydrolysis products from LDPE degradation were detected in the culture media, and the carbon chain lengths of the hydrolysis products detected varied, depending on the species of bacteria. We also determined that C.