Comparative Proteomics of Amylolytic Strains of Bacillus subtilis and Bacillus licheniformis

Bacillus is known to be one of the most important sources of proteins with industrial applications. Not much is known about the local strains of this genus in Nigeria. This study aimed at investigating the comparative proteomics of the intracellular and extracellular proteins from B.subtilis and B. licheniformis to identify proteins of industrial importance. B. subtilis and B.licheniformis strains earlier isolated were reactivated and used in this study. The organisms were incubated at 37 o C and 50 o C. The intracellular and extracellular proteins were extracted from the cells. The proteomes were resolved using one dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis and two dimensional differential gel electrophoresis. The proteins were further analysed using Decyder 2D version 6.0 software and the selected spots were subjected to Trypsin digestion. The peptide‐fragments were eluted into Linear Trapped Quadrupole Mass Spectrometer (LTQ‐MS/MS) and the RAW files obtained were searched against the database of the B. subtilis and B. licheniformis fasta files. The results obtained revealed that B. subtilis at 37 o C secreted alpha‐amylase and YmcB protein extracellularly while the prominent intracellular proteins were bacitracin synthetase and glutathione peroxidase. In contrast, the prominent extracellular proteins secreted by B. licheniformis at 37 o C were leucine aminopeptidase precursor and bacitracin transport ATP binding proteins while the intracellular proteins at 37 o C were homoserine‐O‐succinyl transferase and bacitracin transport ATP binding protein. B. licheniformis grew at 50 o C and produced many proteins. It was concluded that B. licheniformis was a more versatile producer of industrial proteins.