en Screening of Alginate Lyase-Producing Bacteria and Optimization of Media Compositions for Extracellular Alginate Lyase Production Related Fields Related Fields مقاله کامل Full Length/Original Article <p><strong>Background:</strong> Alginate is a linear polysaccharide consisting of guluronate (polyG) and mannuronate (polyM) subunits. <strong>Methods:</strong> In the initial screening of alginate-degrading bacteria from soil, 10 isolates were able to grow on minimal medium containing alginate. The optimization of cell growth and alginate lyase (algL) production was carried out by the addition of 0.8% alginate and 0.2-0.3 M NaCl to the culture medium. Of 10 isolates, one was selected based on its fast growth rate on minimal 9 medium containing 0.4% sodium alginate. The selected bacterium, identified based on morphological and biochemical characteristics as well as 16S rDNA sequence data, was confirmed to be an isolate belonging to the genus <em>Bacillus</em> and designated as <em>Bacillus</em> sp. TAG8. <strong>Resuls</strong><strong>:</strong> The results showed the ability of<em> Bacillus</em> sp. TAG8 to utilize alginate as a sole carbon source. <em>Bacillus</em> sp. TAG8 growth and algL production were augmented with an increase in sodium alginate concentration and also by the addition of 0.2-0.3 M NaCl. Molecular analysis of TAG8 <em>algL </em>gene showed 99% sequence identity with algL of <em>Pseudomonas</em> <em>aeruginosa </em>PAO1. algL produced by <em>Bacillus</em> sp. TAG8 cleaved both polyM and polyG blocks in alginate molecule as well as acetylated alginate residues, confirming the bifunctionality of the isolated lyase. <strong>Conclusion:</strong> The identification of novel <em>algL</em> genes from microbial communities constitutes a new approach for exploring lyases with specific activity against bacterial alginates and may thus contribute to the eradication of persistent biofilms from clinical samples.</p> Alginate, Bacillus spp., Alginate lyase, Pseudomonas biofilm 48 56 http://ibj.pasteur.ac.ir/browse.php?a_code=A-10-1-621&slc_lang=en&sid=1 Hadis Tavafi No Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Tehran, Iran Ahya Abdi- Ali abdialya@alzahra.ac.ir Yes Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Tehran, Iran Parinaz Ghadam No Department of Biotechnology, Faculty of Biological Sciences, Alzahra University, Tehran, Iran Sara Gharavi No Department of Biotechnology, Faculty of Biological Sciences, Alzahra University, Tehran, Iran