Molecular identification and evaluation of the impact of red heat damage causing halophilic microbes on salted hide and skin

Abstract

Salt is widely used as preservative to protect animal skin from microbial attack. However, addition of salt creates a favorable condition for halophilic microorganisms associated with biodeterioration termed red heat damage. Knowledge about microbial diversity associated with red heat damage is expected to help develop appropriate control strategies. The objectives of this study were to isolate and characterize halophiles from salted sheepskin and evaluate their ability to degrade sheepskin. A total of 85 halophiles were isolated from salted sheepskins after enrichment in a medium containing 10%, 20% and 25% (w/v) NaCl and chopped sheepskin. In all the enrichment cultures the sheepskin was completely dissolved by the microbial consortia. Pure culture isolates belonging to the genera Halomonas, Bacillus, Salimicrobium, Nesterenkonia, and Marinococcus within Domain Bacteria and genus Halococcus from Domain Archaea were isolated. When tested independently, the isolates showed variation in their efficiency to hydrolyze sheepskin collagen. Isolate Halococcus sp. s2535 was the fastest in hydrolyzing the skin followed by Nesterenkonia sp. s2011, Marinococcus sp. s2526 and Halococcus sp. s2528. The results of this study demonstrate that halophilic microbes associated with red heat damage of salted sheepskin are highly diverse and preventive measures should target a diverse group of halophilic microbes.