Examination of Haloversatile Bacteria on Salted Goatskin and Inactivation of Haloversatile Bacteria via Direct Electric Current

Abstract

Haloversatile bacteria are among the commonly found microorganisms that have the potential to damage hides and skins in the leather industry. Therefore, the objective of this study was to investigate the presence of haloversatile bacteria on salted goatskins, to characterize these microorganisms through the use of molecular and conventional test methods, to detect their impact on the skins, and finally find an effective solution to inactivate these microorganisms. Haloversatile bacteria were common inhabitants at salted goatskin samples obtained from the Tuzla Organized Leather Industry Zone in Türkiye. Total numbers of haloversatile bacteria, proteolytic haloversatile bacteria, and lipolytic haloversatile bacteria on ten salted goatskin samples ranged from 7×104 to 2.7×105 CFU/g, 1×104 to 8×104 CFU/g, and 1×104 to 1.3×105 CFU/g, respectively. In the present study, 88% of the isolates were protease-positive, 69% were lipase-positive, 8% were xylanase-positive, 27% were caseinase-positive, 23% were amylase-positive, 8% were DNase-positive, 31% were cellulasepositive, 54% were urease-positive, 100% were catalase-positive, and 54% were oxidase-positive. The bacterial isolates showed positive reactions for the utilization of different amino acids such as glycine, L-cysteine, L-proline, and L-threonine, having the highest rates of 88%, 80%, 80%, and 80%, respectively. However, L-histidine had a lower positive reaction rate of 31%. The halophilic bacterial isolates exhibited positive reactions for the utilization and acid production from different types of sugar, with glucose having the highest positive reaction rate of 81%, followed by maltose at 73%, xylose at 58%, galactose at 46%, and lactose at 42%. Haloversatile enzymeproducing bacteria were identified using biochemical and molecular methods, resulting in the identification of 17 different species. Micrographs obtained from the scanning electron microscope revealed the damage inflicted on the fresh goatskin structure by haloversatile bacteria. A direct electric current of 2.2 A was applied to the mixed culture of haloversatile bacteria for 25 minutes to find an effective inactivation method. The total count of the mixed culture of haloversatile bacteria decreased from 7.3×106 CFU/mL to 4 CFU/mL within 16 minutes. All seventeen haloversatile bacteria in the mixed culture were killed within 19 minutes.