Identification and Characterization of “Red Heat” Damage Causing Halophilic Microbes on Salted Sheepskin
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Date
2018-12-03
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Addis Ababa University
Abstract
A number of factors cause damage of skin and hide. Among these the major factor that did not
get the attention of all stakeholders in Ethiopia is the “red heat” damage caused by halophilic
microbes on salted skins and hides. Tanners and foreign buyers reject salted skins and hides
affected by “red heat” damage. The objective of this study was to identify and characterize
halophilic microbes causing “red heat” damage of salted skins and hides using culturedependent
and molecular methods. Halophilic and halotolerant bacteria and archaea were
isolated and characterized from the “red heat” damaged salt cured sheepskins, with visible red
patches. The enrichment microbial community was shifted from bacteria to archaea through
time. A total of 85 isolates were obtained from 10%, 20% and 25% salt concentration
enrichment microbial communities. Members of bacterial domain were the most abundant
(89%), while members of domain Archaea were found to be 11% all belong to archaeal phylum
Euryarchaeota. The enrichment bacterial isolates were clustered to three phyla, namely;
Actinobacteria, Firmicutes and Proteobacteria. The bacterial enrichment isolates were affiliated
to members of five genera: Halomonas, Bacillus, Salimicrobium, Nesterenkonia, Marinococcus,
and Nesterenkonia. All the isolates belonged to Archaea were affiliated to members of genus
Halococcus. Among the 17 representative isolates tested for their ability to degrade collagen, the
archaeal isolate Halococcus sp. s2535 showed the maximum degree of hydrolysis followed by
bacterial isolates Nesterenkonia sp.s211, Marinococcus sp. s2526 and archaeal isolate
Halococcus sp. s2528. The phylogenetic analysis of isolates showed that most of the isolates
were closely related to halophilic microbes obtained from various hypersaline environments,
fermented foods and salted skins and hides. The result of this study indicates that microbes
causing “red heat” damage of salted skin and hide are diverse and halotolerant. Although
halophilic microbes growing at high salt concentration are the most efficient collagen
degraders, those growing at low salt concentration also have certain degree of contribution.
Therefore, an attempt to prevent the impact of halophilic microbes on salted skin and hide
should address the diverse groups of microbes.
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Keywords
Skin Defect, Collagen, Skin Degradation, Salt Preservation, Skin and Hide