Prevalence of potentially thermophilic microorganisms in biofilms from greenhouse-enclosed drip irrigation systems
Drip irrigation systems using reclaimed water often present clogging events of biological origin. Microbial communities in biofilms from microirrigation systems of an experimental greenhouse in Almería, SE Spain, which used two different qualities of water (treated wastewater and reclaimed water), were analyzed by denaturing gradient gel electrophoresis and subsequent sequencing of amplified 16S rRNA gene bands. The most remarkable feature of all biofilms was that regardless of water origin, sequences belonging to Firmicutes were prevalent (53.5 % of total mean band intensity) and that almost all sequences recovered had some similarity (between 80.2 and 97 %) to thermophilic microorganisms. Mainly, sequences were closely related to potentially spore-forming organisms, suggesting that microbial communities able to grow at high temperatures were selected from the microbiota present in the incoming water. These pioneer results may contribute to improve management strategies to minimize the problems associated to biofouling in irrigation systems.
KeywordsDGGE 16S rRNA gene Thermophilic bacteria Biofilms Wastewater reuse
This work was supported by Grants CSD2006-00044 TRAGUA (CONSOLIDER-INGENIO2010) and CTQ2009-14390-C02-02 from the Spanish Ministry of Education and Science to J.M., and PET2008-0165-02 to O.S.
- Iino T, Mori K, Uchino Y, Nakagawa T, Harayama S, Suzuki K (2010) Ignavibacterium album gen. nov., sp. nov., a moderately thermophilic anaerobic bacterium isolated from microbial mats at a terrestrial hot spring in Japan and proposal of Ignavibacteria classis nov., for a novel lineage at the periphery of green sulfur bacteria. Int J Syst Evol Microbiol 60:1376–1382PubMedCrossRefGoogle Scholar
- Muñoz I, Gómez MM, Férnandez-Alba AR (2010) Life cycle assessment of biomass production in a Mediterranean greenhouse using different water sources, groundwater, treated wastewater and desalinated seawater. Agric Syst 10:31–39Google Scholar
- Muyzer G, Brinkhoff T, Nübel U, Santegoeds C, Schäfer H, Wawer C (1998) Denaturing gradient gel electrophoresis DGGE in microbial ecology. In: Akkermans ADL, van Elsas JD, Bruijn FJ (eds) Molecular microbial ecology manual. Kluwer, Dordrecht, pp 1–27Google Scholar
- Nazina TN, Tourova TP, Poltaraus AB et al (2001) Taxonomic study of aerobic thermophilic bacilli, descriptions of Geobacillus subterraneus gen. nov., sp. nov. and Geobacillus uzenensis sp. nov. from petroleum reservoirs and transfer of Bacillus stearothermophilus, Bacillus thermocatenulatus, Bacillus thermoleovorans, Bacillus kaustophilus, Bacillus thermoglucosidasius and Bacillus thermodenitrificans to Geobacillus as the new combinations G. stearothermophilus, G. thermocatenulatus, G. thermoleovorans, G. kaustophilus, G. thermoglucosidasius and G. thermodenitrificans. Int J Syst Evol Microbiol 51:433–446PubMedGoogle Scholar
- Oksanen J, Blanchet FG, Kindt R, Legendre P, Minchin PR, O’Hara RB et al (2013) Vegan: community ecology package. R package version 2.0-7. http://cran.r-project.org/web/packages/vegan/index.html
- Sullivan RF, Holtman MA, Zylstra GJ, White JF, Kobayashi DY (2003) Taxonomic positioning of two biological control agents for plant diseases as Lysobacter enzymogenes based on phylogenetic analysis of 16S rDNA, fatty acid composition and phenotypic characteristics. J Appl Microbiol 94:1079–1086PubMedCrossRefGoogle Scholar