Increased chemotaxis towards xylan and hemicellulose from Paenibacillaceae isolates

RAGOUT AL; DÁVILA-COSTA MJ; VALDEÓN D; PEROTTI NI; ABATE CM; MARTÍNEZ MA1

Cordoba, Argentina

Congreso; VI Congreso Argentino de MIcrobiolog¡ia General (SAMIGE); 2009

Sociedad Argentina de Microbiologia General

Bacterial chemotaxis is a primitive mechanism by which bacteria responds to high concentrations of attractants and is activated by changes in pH, temperature, osmolarity, viscosity and chemical compounds, some of which are nutrients and secondary metabolites. Most motile bacteria can sense and respond to low concentration of attractants. There is evidence that chemotaxis can enhance biodegradation, presumably by rapidly bringing cells into close contact with degradable substrates. Isolates AR92 and AR109, related to Paenibacillaceae were obtained from bagasse liquor and were Gram + bacillus, mobile, catalase positive Scanning electron microscopy showed the presence of polar flagella in both strains as a physiological property related to bacterial motility.Swimming ability related with chemotaxis was evaluated in minimal media with birchwood xylan and hemicellulose extracted from sugar cane bagasse with the addition of Tween 80 and divalent cations in plates solidified with agarose 0.3%.  Results showed that isolate AR 109 exhibited higher swimming, apparently masking the clarification of medium owed to xylan hydrolysis. This effect was significantly enhanced when calcium and magnesium salts as well as Tween 80 were added to final concentrations of 20 mM and 0.2%.y. Isolate AR92 behavior was different, showing discrete colonies surrounded by clarification hydrolysis halos.As a whole, behavior of both isolates tested was for the most part modified by the nutrients added to the media. Regarding the carbon source both, colony size and halos, were higher when  birchwood xylan was used.