APPLIED MICROBIAL AND CELL PHYSIOLOGY Action of antimicrobial substances produced by different oil reservoir Bacillus strains against biofilm formation E. Korenblum & G. V. Sebastián & M. M. Paiva & C. M. L. M. Coutinho & F. C. M. Magalhães & B. M. Peyton & L. Seldin Received: 28 November 2007 / Revised: 2 February 2008 / Accepted: 4 February 2008 / Published online: 11 March 2008 # Springer-Verlag 2008 Abstract Microbial colonization of petroleum industry systems takes place through the formation of biofilms, and can result in biodeterioration of the metal surfaces. In a previous study, two oil reservoir Bacillus strains (Bacillus licheniformis T6-5 and Bacillus firmus H 2 O-1) were shown to produce antimicrobial substances (AMS) active against different Bacillus strains and a consortium of sulfate- reducing bacteria (SRB) on solid medium. However, neither their ability to form biofilms nor the effect of the AMS on biofilm formation was adequately addressed. Therefore, here, we report that three Bacillus strains (Bacillus pumilus LF4—used as an indicator strain, B. licheniformis T6-5, and B. firmus H 2 O-1), and an oil reservoir SRB consortium (T6lab) were grown as biofilms on glass surfaces. The AMS produced by strains T6-5 and H 2 O-1 prevented the formation of B. pumilus LF4 biofilm and also eliminated pre-established LF4 biofilm. In addi- tion, the presence of AMS produced by H 2 O-1 reduced the viability and attachment of the SRB consortium biofilm by an order of magnitude. Our results suggest that the AMS produced by Bacillus strains T6-5 and H 2 O-1 may have a potential for pipeline-cleaning technologies to inhibit biofilm formation and consequently reduce biocorrosion. Keywords Bacillus licheniformis . Bacillus firmus . Antimicrobial substances . Biofilm . Sulfate-reducing bacteria (SRB) Introduction Biofilms are cells attached to a surface and encased in an exopolysaccharide matrix forming a structured community (Hamon and Lazazzera 2001). Most bacteria can attach to surfaces efficiently when they are viable and in a metabolically active state (Jayaraman et al. 1997). A variety of Bacillus species have been shown to form biofilms on metal surfaces and produce elaborate multicellular commu- nities that display conspicuous architectural features, such as fruiting-body-like aerial projections that extend from the biofilm surface (Branda et al. 2004). The top or base of the biofilm has the highest cell density, and water channels often exist for the transport of nutrients and waste (Ren et al. 2002). In addition, some Bacillus species produce highly hydrophobic spores that adhere firmly to various inert substrata. Once this first step of adhesion has been completed, colonization may occur when environmental conditions become favorable to spore germination (Branda et al. 2004; Faille et al. 2001). In the Appl Microbiol Biotechnol (2008) 79:97–103 DOI 10.1007/s00253-008-1401-x E. Korenblum : L. Seldin (*) Laboratório de Genética Microbiana, Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Bloco I, Ilha do Fundão, CEP 21941-590 Rio de Janeiro, RJ, Brazil e-mail: lseldin@micro.ufrj.br G. V. Sebastián CENPES, Petrobras, Brazil M. M. Paiva : C. M. L. M. Coutinho : F. C. M. Magalhães Laboratório de Biologia Celular, Instituto Oswaldo Cruz, FIOCRUZ, RJ, Brazil C. M. L. M. Coutinho Departamento de Biologia Celular e Molecular, Instituto de Biologia, Universidade Federal Fluminense-UFF, Niterói, RJ, Brazil B. M. Peyton Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA