Production and Purification of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Degrading Enzyme from Streptomyces sp. AF-111

A poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) degrading bacterial strain designated as AF-111 was isolated from sewage sludge sample. The bacterium was identified by 16S rRNA gene sequencing. The results revealed that strain AF-111 showed 99 % similarity with Streptomyces althioticus strain NRRL B-3981 and designated as Streptomyces sp. strain AF-111. An extracellular PHBV depolymerase enzyme was produced under optimized conditions and purified through ammonium sulphate fractionation and column chromatography. The enzyme was purified to homogeneity, indicated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and molecular weight was found to be approximately 51 kDa. Effect of temperature, pH, metal ions and inhibitors on the PHBV depolymerase activity was determined. The enzyme was stable at wide range of temperature (35–55 °C) and pH (6–8). PHBV depolymerase was stable in the presence of different metal ions except iron and zinc which had inhibitory effect on depolymerase activity. Both ethylenediamine teteracetic acid and phenylmethyl sulphonyl fluoride strongly inhibited enzyme activity which indicates that this enzyme belongs to the serine hydrolase family like other polyhydroxyalkanoate depolymerases. The results show that a depolymerase from strain AF-111 can effectively degrade PHBV, therefore, it can be applied in the process of biochemical monomer recycling.     

Myco- and phyco-remediation of polychlorinated biphenyls in the environment: a review

Environmental Science and Pollution Research - Polychlorinated biphenyls (PCBs) are toxic organic compounds and pose serious threats to environment and public health. PCBs still exist in different...     

Enhancement of biomethane production from cattle manure with codigestion of dilute acid pretreated lignocellulosic biomass

It is well known that dilute sulfuric acid pretreatment of the lignicellulosisc biomass is an effective approach used for the production of the ethanol. However, there are less studies on the biogas production from the pretreated lignocellulosics and hardly data available on the codigestion of cattle manure with the pretreated lignocellulosisc material. The aim of this study was to evaluate biomethane production potential of codigestion of cattle manure with dilute acid pretreated lignocellulosic biomass. Sugarcane bagasse and rice husk was pretreated with dilute sulfuric acid or phosphoric acid at 121°C for 20 minutes and subsequently subjected to anaerobic digestion alone or codigested with cattle manure.

The results showed that codigestion of 1% phosphoric acid pretreated rice husk with cattle manure led to the highest methane production of 115 Nmlg^?1VS while monodigestion of cattle manure and phosphoric acid pretreated rice husk produced 98 and 87 Nmlg^?1VS, respectively. An inhibition was observed in anaerobic digestion of sulfuric acid pretreated rice husk and sugarcane bagasse during monodigestion and codigestion with cattle manure.

The study concludes that dilute phosphoric acid pretreated lignocellulosics like sugarcane bagasse and rice husk can be used as a cosubstrate with cattle manure in anaerobic digestion for enhanced methane production. Dilute sulfuric acid pretreatment, which is effective method for the bioethanol production, causes inhibition during anaerobic digestion of the pretreated lignocellulosics.     

Microalgae binary culture for higher biomass production,nutrients recycling,and efficient harvesting: a review

Environmental Chemistry Letters - Microalgae are photosynthetic cell factories of global interest for fuels, food, feed, bioproducts, carbon sequestration, waste mitigation, and environmental...