ABSTRACT
From an agricultural sample taken in Chongqing, a stable methane-oxidizing mixed microbial consortium was established by enrichment culture with methane as a sole source of carbon and energy. The mixed consortium showed high capability of phenol degradation and 1,2-epoxypropane production from propene. More than 99% of phenol at an initial concentration of 600mg/L could be degraded by the mixed microbial consortium after 11 h of cultivation. The productivity of 1, 2-epoxypropane could be increased with the decrease of phosphate concentration. The concentration of 1, 2-epoxypropane produced could reach to 5.0mmol/L. The bacterial structure of the methane-oxidizing mixed microbial consortium was analyzed by pure culture isolation combining with 16S rRNA and PCR of the related MMO functional genes. The results showed that the methane-oxidizing mixed microbial consortium was composed of a type 1U methanotroph identified as Methylosinus trichosporium and at least 4 kinds of heterotrophs ( Comamonas testosteroni, Cupriavidus metallidurans, Acinetobacter junii and Stenotrophomonas maltophilia ). M. trichosporium Y9, isolated from the mixed consortium, harbored both sMMO and pMMO genes.
Subject(s)
Bacteria/metabolism , Methane/metabolism , Soil Microbiology , Bacteria/growth & development , Epoxy Compounds/metabolism , Methylosinus/metabolism , Oxygenases/genetics , Oxygenases/metabolism , Phosphates/pharmacologyABSTRACT
Pseudomonas delafieldii was immobilized in magnetic polyvinyl alcohol (PVA) beads using a hydrophilic magnetic fluid, which was prepared by a co-precipitation method. The beads had distinct super-paramagnetic properties and were compared with immobilized cells in non-magnetic PVA beads. Their desulfurizing activity was increased slightly from 8.7 to 9 mmol sulfur kg(-1) (dry cell) h(-1). The main advantages was that the magnetic immobilized cells maintain a high desulfurization activity and remain in good shape after 7 times of repeated use, while the non-magnetic immobilized cells could only be used for 5 times. Furthermore, the magnetic immobilized cells could be easily collected or separated magnetically from the biodesulfurization reactor.
