Abstract
Aim: Whole genome sequencing and functional annotation of Bacillus nealsonii strain AAU1, an amylolytic anaerobic spore forming isolate from ruminal contents of buffalo. Methods and Results: Morphologically, the strain was observed as slender Grampositive rods, occurring in pairs. Optimal growth was observed at 40°C (range: 30°C to 45°C) and pH 6.5 (range: 5.5 to 7.5) when cultivated in Hungate’s medium supplemented with starch. The microorganism showed extracellular constitutive amylolytic activity, proving to be capable of utilizing glucose, maltose, mannose, trehalose, dextrin and starch under anaerobic conditions. Sequence analysis revealed a GC content of 35.1 mol%. Comparison of housekeeping gene sequences for RNA polymerase subunit B (rpoB) and gyrase A (gyrA) identified sequence similarity within the Bacillus genus, confirmed by 16S rRNA gene sequence similarity which identified Bacillus nealsonii DSM 15077 as the closest publically available relative. Chemotaxonomic analysis provided conflicting results with straight-chain saturated C16: 0/C16:0 aldehyde, C16:0 DMA, C14:0 and monounsaturated 16:1w7c and 16:1w9c the major fatty acids in contrast to those reported for B. nealsonii DSM15077. Further characterization using AN-Bilog and physiological parameters provided genotypic and phenotypic support for taxonomic classification of isolate AAU1 with published Bacillus species including B. licheniformis, B. subtilis, B. circulans and B. nealsonii. Conclusion: Based on the data presented, isolate is likely to represent a new strain/subspecies, for which the identifier B. nealsonii AAU1 is proposed. Significance and Impact of Study: The strict anaerobic conditions prevailing in the bovine rumen from where AAU1 was isolated may have resulted in genetic polymorphism influencing its metabolic characteristics.
Highlights
The rumen harbors a large and diverse range of microorganisms categorized into Bacteria, Archaea and Eucarya [1]
We describe here the isolation and characterization by sequencing and biochemical analysis of a putatively new B. nealsonii strain or isolate with relevance to the future understanding and improvement of ruminant health and nutrition
Some genes are shared by a vast majority of bacterial species, including the ribosomal genes and housekeeping genes such as RNA polymerase subunit B (rpoB), gyrase A (gyrA) and homologous recombination-associated recA, offering possibilities as universal targets for identification and taxonomy [12]
Summary
The rumen harbors a large and diverse range of microorganisms categorized into Bacteria, Archaea (methanogens) and Eucarya (protozoa and fungi) [1]. Obligatory anaerobes are dominated and supplemented by facultative anaerobes including Streptococcus, Staphylococcus, Bacillus and Lactobacillus species [2]. The Bacillus genus, introduced by Cohn in the year 1872, comprises more than 200 species and is considered to be among the largest bacterial genera with new additions identified every year. The Bacilli are rod shaped gram positive bacteria, and characterized by spore forming ability and aerobic or facultative anaerobic metabolism [3]. Single spores are formed per cell in response to environmental stress, such as heat, cold, radiation or desiccation; features which support their existence in extreme habitats include desert sands, hot springs and Arctic soils. Sequencing bacterial genomes provide insight into the genetic basis of phenotypic plasticity and their ability to tolerate environmental stresses [4].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
