Cellulolytic bacteria from soils in harsh environments
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It is believed that the exposure of organisms to harsh climate conditions may select for differential enzymatic activities, making the surviving organisms a very promising source for bioprospecting. Soil bacteria play an important role in degradation of organic matter, which is mostly due to their ability to decompose cellulose-based materials. This work focuses on the isolation and identification of cellulolytic bacteria from soil found in two environments with stressful climate conditions (Antarctica and the Brazilian semi-arid caatinga). Cellulolytic bacteria were selected using enrichments at high and low temperatures (4 or 60°C) in liquid media (trypic soy broth—TSB and minimum salt medium—MM) supplemented with cellulose (1%). Many of the isolates (119 out of 254—46.9%) displayed the ability to degrade carboxymethyl-cellulose, indicating the presence of endoglucolytic activity, while only a minority of these isolates (23 out of 254—9.1%) showed exoglucolytic activity (degradation of avicel). The obtained isolates revealed a preferential endoglucolytic activity according to the temperature of enrichments. Also, the identification of some isolates by partial sequencing of the 16S rRNA gene indicated that the Bacteroidetes (e.g., Pedobacter, Chryseobacterium and Flavobacterium) were the main phylum of cellulolytic bacteria isolated from soil in Antarctica; the Firmicutes (e.g., Bacillus) were more commonly isolated from samples from the caatinga; and Actinobacteria were found in both types of soil (e.g., Microbacterium and Arthrobacter). In conclusion, this work reports the isolation of bacteria able to degrade cellulose-based material from soil at very low or very high temperatures, a finding that should be further explored in the search for cellulolytic enzymes to be used in the bioenergy industry.
KeywordsAntarctica Caatinga Cellulose Endoglucanase Exoglucanase
This work was financially supported by Embrapa. We also thank Dr. Vivian H. Pellizari for the soil samples from Antarctica and the Brazilian Marine corps for support during the Antarctica expeditions.
- Clarke A (2003) Evolution, adaptation and diversity: global ecology in an Antartic context. Antar Biol in a Glo Context 3–17Google Scholar
- Hendricks CW, Doyle JD, Hugley B (1995) A new solid medium for enumerating cellulose utilizing bacteria in soil. Appl Environ Microbiol 61:2016–2019Google Scholar
- Margesin R, Feller G (2010) Biotechnol Appl psychrophiles Environ Technol 31:835–844Google Scholar
- Martinez-Sáchez JL (2005) Nitrogen and phosphorus resorption in a neo tropical rain forest of a nutrient-rich soil. Rev Bio Trop 53:193–206Google Scholar
- Peng G, Zhu W, Wang H, Lu Y, Wang X, Zheng D, Cui Z (2010) Functional characteristics and diversity of a novel lignocelluloses degrading composite microbial system with high xylanase activity. J Microbiol Biotechnol 20:254–264Google Scholar
- Rademaker JLW, Louws FJ and De Bruijn FJ (1997) Characterization of the diversity of ecologically impornant microbes by rep-PCR genomic fingerprinting. In: Akkermans ADL, Van Elsas JD and De Bruijn JD. Molecular Microbial Ecology Manual, Kluwer Academic Publishers, Dordrecht, Supplement 3, chapter 3.4.3, pp. 1–26Google Scholar
- Rastogi G, Muppidi GL, Gurram RN, Adhikari A, Bischoff KM, Hughes SR, Apel WA, Bang SS, Dixon DJ, Sani RK (2009) Isolation and characterization of cellulose bacteria from the deep subsurface of the Homestake gold mine, Lead, South Dakota, USA. J Indus Microbiol Biotechnol 36:585–598CrossRefGoogle Scholar
- Sinegani AAS, Mahohi A (2010) Soil water potential effects on the cellulase activities of soil treated with sewage sludge. Plant Soil Environ 56:333–339Google Scholar
- Teather RM, Wood PJ (1982) Use of Congo red-polissaccahride interactions in enumeration and characterization on cellulolytic bacteria from the bovine rumen. Appl Environ Microbiol 43:777–780Google Scholar