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Background For microorganisms on a paper surface, the lack of water is one of the most important stress factors. A strain of Bacillus megaterium FDU301 was isolated from plaques on a paper surface using culture medium with polyethylene glycol 200 (PEG200) to simulate an arid condition. Global transcriptomic analysis of B. megaterium FDU301 grown under normal and simulated arid conditions was performed via RNA-seq technology to identify genes involved in arid stress adaptation. Results The transcriptome of B. megaterium FDU301 grown in LB medium under arid (15% PEG200 (w/w)) and normal conditions were compared. A total of 2941 genes were differentially expressed, including 1422 genes upregulated and 1519 genes downregulated under arid conditions. Oxidative stress-responsive regulatory genes perR, fur, and tipA were significantly upregulated, along with DNA protecting protein (dps), and catalase (katE). Genes related to Fe2+ uptake (feoB), sporulation stage II (spoIIB, spoIIE, spoIIGA), small acid-soluble spore protein (sspD), and biosynthesis of compatible solute ectoine (ectB, ectA) were also highly expressed to various degrees. Oxidative phosphorylation-related genes (atpB, atpE, atpF, atpH, atpA, atpG, atpD, atpC) and glycolysis-related genes (pgk, tpiA, frmA) were significantly downregulated. Conclusion This is the first report about transcriptomic analysis of a B. megaterium to explore the mechanism of arid resistance. Major changes in transcription were seen in the arid condition simulated by PEG200 (15%), with the most important one being genes related to oxidative stress. The results showed a complex mechanism for the bacteria to adapt to arid stress.

WOS: 000462022300057 PubMed: 30474775 A newly identified ligninolytic Rhodococcus strain (Rhodococcus sp. T1) was isolated from forestry wastes (Trabzon/Turkey). The DyP type peroxidase of Rhodococcus sp. T1 (DyPT1) was cloned, characterized and paper treated for industrial applications. Molecular weight of the protein was about 38kDa. The kinetic parameters were 0.94mM and 1417.53 mu mol/min/mg for Km and Vmax, respectively. The enzyme was active at the temperature range of 25-65 degrees C and optimum temperature was 35 degrees C, enzyme was stable up to 6 days at room temperature. Optimum pH of the DyPT1 was 4.0 and it was stable between pH 4.0-6.0 up to 8 days at room temperature. Effects of some metal ions, Hemin, and some chemical agents on DyPT1 were determined. Hemin has implemented protective effects on the stability and the activity of the enzyme in long time periods when added into growing medium. DyPT1 was applied to eucalyptus kraft pulp for analyzing the bleaching efficiency, physical and optical tests of the manufuctared paper were carried out. Application of lignin peroxidase to kraft pulp caused a decrease of 5.2 units for kappa number and an increase from 52.05 to 64.18% in the delignification rate. Karadeniz Technical University Research Foundation [FBA-2015-5182] This study was financially supported by Karadeniz Technical University Research Foundation (Project No: FBA-2015-5182).