Neotropical termite microbiomes as sources of novel plant cell wall degrading enzymes

Romero Victorica, Matías. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnología y Biología Molecular (IABIMO). Hurlingham, Buenos Aires, Argentina.Soria, Marcelo Abel. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola. Buenos Aires, Argentina.Batista García, Ramón Alberto. Universidad Autónoma del Estado Morelos. Instituto de Investigación en Ciencias Básicas y Aplicadas. Centro de Investigación en Dinámica Celular. Cuernavaca, Morelos, Mexico.Ceja Navarro, Javier A. Biological Systems and Engineering Division. Lawrence Berkeley National Laboratory. Berkeley, California, USA.Vikram, Surendra. Department Biochemistry, Genetics and Microbiology. Centre for Microbial Ecology and Genomics. University of Pretoria. Pretoria, South Africa.Ortiz, Maximiliano. University of Pretoria. Centre for Microbial Ecology and Genomics. Genetics and Microbiology. Pretoria, South Africa.Ontañon, Ornella. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnología y Biología Molecular (IABIMO). Hurlingham, Buenos Aires, Argentina.Ghio, Silvina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnología y Biología Molecular (IABIMO). Hurlingham, Buenos Aires, Argentina.14In this study, we used shotgun metagenomic sequencing to characterise the microbial metabolic potential for lignocellulose transformation in the gut of two colonies of Argentine higher termite species with diferent feeding habits, Cortaritermes fulviceps and Nasutitermes aquilinus. Our goal was to assess the microbial community compositions and metabolic capacity, and to identify genes involved in lignocellulose degradation. Individuals from both termite species contained the same fve dominant bacterial phyla (Spirochaetes, Firmicutes, Proteobacteria, Fibrobacteres and Bacteroidetes) although with diferent relative abundances. However, detected functional capacity varied, with C. fulviceps (a grass-wood-feeder) gut microbiome samples containing more genes related to amino acid metabolism, whereas N. aquilinus (a wood-feeder) gut microbiome samples were enriched in genes involved in carbohydrate metabolism and cellulose degradation. The C. fulviceps gut microbiome was enriched specifcally in genes coding for debranching- and oligosaccharide-degrading enzymes. These fndings suggest an association between the primary food source and the predicted categories of the enzymes present in the gut microbiomes of each species. To further investigate the termite microbiomes as sources of biotechnologically relevant glycosyl hydrolases, a putative GH10 endo-β-1,4- xylanase, Xyl10E, was cloned and expressed in Escherichia coli. Functional analysis of the recombinant metagenome-derived enzyme showed high specifcity towards beechwood xylan (288.1 IU/mg), with the optimum activity at 50°C and a pH-activity range from 5 to 10. These characteristics suggest that Xy110E may be a promising candidate for further development in lignocellulose deconstruction applications