title: Microbial community development of biofilm in Amaranth decolourization technology analysed by FISH.
abstract: The aim of this study was to elucidate the role, the space distribution and the relationships of the bacteria from the genusPseudomonasin a biofilm community during semi-continuous Amaranth decolourization process in model sand biofilters. The examined parameters of the process were as follows: technological parameters; key enzyme activities (azoreductase, succinate dehydrogenase, catechol-1,2-dioxygenase, catechol-2,3-dioxygenase); the number of azo-degrading bacteria and the bacteria from genusPseudomonas(plate count technique); the amount and the location ofPseudomonassp. using fluorescent in situ hybridization (FISH). The results showed that the increase of the Amaranth removal rate with 120% was accompanied with increase of the enzyme activities of the biofilm (azoreductase activity - with 25.90% and succinate dehydrogenase - with 10.61%). The enzyme assays showed absence of activity for сatechol-1,2-dioxygenase and catechol-2,3-dioxygenase at the early phase and high activities of the same oxygenases at the late phase (2.76 and 1.74 μmol/min mg protein, respectively). In the beginning of the process (0-191 h), the number of the culturable microorganisms from genusPseudomonaswas increased with 48.76% but at the late phase (191-455 h) they were decreased with 15.25% while the quantity of the non-culturable bacteria from this genus with synergetic relationships was increased with 23.26%. The dominant microbial factors were identified in the structure of the biofilm during the azo-degradation process by using FISH analysis. Furthermore, the inner mechanisms for increase of the rate and the range of the detoxification were revealed during the complex wastewater treatment processes.
authors.affiliation: Faculty of Biology, Sofia University 'St. Kliment Ohridski' , Sofia , Bulgaria.
authors.forename: Mihaela
authors.initials: M
authors.lastname: Belouhova
authors.affiliation: Faculty of Biology, Sofia University 'St. Kliment Ohridski' , Sofia , Bulgaria.
authors.forename: Irina
authors.initials: I
authors.lastname: Schneider
authors.affiliation: Faculty of Biology, Sofia University 'St. Kliment Ohridski' , Sofia , Bulgaria.
authors.forename: Stoyan
authors.initials: S
authors.lastname: Chakarov
authors.affiliation: Faculty of Biology, Sofia University 'St. Kliment Ohridski' , Sofia , Bulgaria.
authors.forename: Iliana
authors.initials: I
authors.lastname: Ivanova
authors.affiliation: Faculty of Biology, Sofia University 'St. Kliment Ohridski' , Sofia , Bulgaria.
authors.forename: Yana
authors.initials: Y
authors.lastname: Topalova
keywords: Amaranth; Pseudomonas sp.; fluorescent in-situ hybridization; non-culturable bacteria; technological parameters; wastewater treatment