title: Biofilm growth kinetics of a monomethylamine producing Alphaproteobacteria strain isolated from an anaerobic reactor.
abstract: Industrial fishing effluents are characterized by high loads of protein and sulfate that stimulate the activity of proteolytic and sulfate reducing bacteria during anaerobic digestion. Their metabolic products (NH3 and H2S respectively) have a well-known detrimental effect on the activity of methanogens. Since methylamine is a carbon source used by methylaminotrophic methane producing archaea (mMPA) but not by sulfate reducing bacteria (SRB), enriched mMPA anaerobic biofilms have been developed on ceramics. We propose that methylated amines could be produced in the biofilm by using betaine, a known precursor of methylamine, as a carbon and energy source. We isolated an anaerobic betainotrophic methylaminogenic bacterial strain (bMB) from an anaerobic bioreactor, using betaine as the only carbon and energy source. This strain was identified by a standard biochemical test (API 20NE), cloning, and 16S rDNA sequencing. bMB biofilm structure and biofilm growth kinetic parameters were determined by means of scanning electron microscopy (SEM), and the Gompertz growth model, respectively. Monomethylamine production was determined by infrared spectroscopy and by high pressure liquid chromatography. The isolated bMB strain was determined as Stappia stellulata (Proteobacteria phylum). It was able to form biofilm on ceramics and its kinetic growth parameters resulted in: maximum biofilm bacterial count (A) of 6.25 x 10(8) UFC/cm(2) and maximum specific growth rate (mu(m)) of 0.0221/h. Production of monomethylamine was about 4.027 atogram/cell/day (at/cell/day) after 15 days of incubation in biofilms. This study confirms the adhesion capacity of this bMB strain on ceramic supports, assuring that monomethylamine production in biofilms could be enriched with mMPA that use monomethylamine.
authors.affiliation: Laboratorio de Biopelículas y Microbiología Ambiental, Centro de Biotecnología, Universidad de Concepción, P.O. Box 160C, Concepción, Chile.
authors.forename: Paz
authors.initials: P
authors.lastname: Jopia
authors.forename: Nathaly
authors.initials: N
authors.lastname: Ruiz-Tagle
authors.forename: Marcelo
authors.initials: M
authors.lastname: Villagrán
authors.forename: Katherine
authors.initials: K
authors.lastname: Sossa
authors.forename: Silvio
authors.initials: S
authors.lastname: Pantoja
authors.forename: Luis
authors.initials: L
authors.lastname: Rueda
authors.forename: Homero
authors.initials: H
authors.lastname: Urrutia-Briones
mesh_terms: D020561:Alphaproteobacteria / Q000145:classification / Q000254:growth & development* / Q000302:isolation & purification / Q000378:metabolism*; D015373:Bacterial Typing Techniques; D001622:Betaine / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D019149:Bioreactors / Q000382:microbiology*; D002516:Ceramics; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D008744:Methylamines / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D008744:Methylamines; D012336:RNA, Ribosomal, 16S; D001622:Betaine; C027451:methylamine