en Public Health Public Health پژوهشي Original Article <p><span style="font-size:14px;"><span style="font-family: times new roman;"><strong>Background;</strong> Feather waste is generated in large amounts as a by-product of commercial poultry processing. The main component of feather is keratin. The main purpose of this study was to identify <em>Bacillus spp</em>. (the keratinolytic bacteria) that are able to degrade the feather for producing keratin.<br> <strong>Methods; </strong><em>Bacillus spp</em>. Were isolated from the waste of poultries located in Miyaneh city. The bacteria were grown on basal medium containing 1% hen feather as the sole source of carbon ,nitrogen, sulfur and energy at 27&ordm;C for 7 days. Then,the isolates capable of feather degrading were identified. The Bradford method was used to assay the production of keratin in the feather samples. Different pH and temperatures were studied to determine the best conditions for production of keratinase enzyme.<br> <strong>Results; </strong>Seven <em>Bacillus spp</em>. including: B. <em>pumilis,</em> B. <em>subtilis</em>, B. <em>firmus</em>, B. <em>macerance</em>, B. <em>popilliae</em>, B. <em>lentimorbus</em> and B. <em>larvae</em> were found to be able to degrade the feather with different abilities.<br> <strong>Conclusion; </strong>B. <em>subtilis</em> was found to be most productive isolate for keratinase enzyme production.</span></span></p> Bacillus Spp., Decomposing feathers, Keratinase enzyme, Poultry waste 39 46 http://jhehp.zums.ac.ir/browse.php?a_code=A-10-70-4&slc_lang=en&sid=1 Somayeh Mousavi saloutim@yahoo.com 10031947532846009383 10031947532846009383 No Department of Microbiology, Faculty of Sciences, Zanjan Branch, Islamic Azad University, Zanjan, Iran. Mojtaba Salouti saloutim@yahoo.com 09121454954 10031947532846009384 Yes Biology Research Center, Zanjan Branch, Islamic Azad University, Zanjan, Iran. Reza Shapoury saloutim@yahoo.com 10031947532846009385 10031947532846009385 No Biology Research Center, Zanjan Branch, Islamic Azad University, Zanjan, Iran.