DOI: https://doi.org/10.55373/mjchem.v25i5.88

Keywords: Protease; chicken feather; halophilic; keratinase

Abstract

High salt tolerant extracellular proteases are enzymes that play an important role in industries that require high salt conditions. High salt tolerant extracellular proteases can be produced by halophilic microbes. This research has succeeded in isolating several halophilic microbes capable of producing extracellular proteases from Bledug Kuwu volcanic mud, Grobogan, Central Java, Indonesia. Five isolates tested had bacillus cell shape and were moderate halophilic bacteria. These isolates also produced extracellular proteases on skim milk substrate media in the pH range of 6-9 and the optimum fermentation time was 3-4 days. The extracellular proteases produced by these isolates worked optimally in the pH range of 8-9, the temperature of 40-52 °C, and tolerant at 3-10% NaCl. Extracellular proteases from isolates BK1A and BK1C worked optimally in the presence of Mg2+. BK1H extracellular protease activity works optimally in the presence of Ca2+. All isolates produced extracellular proteases that have keratinase activity that can degrade keratin in chicken feathers with an optimum incubation time of 3-4 days, as proven by the % weight loss on day 5 of 12.2%; 20.9%; 12.3%; 16.4%; and 35.8%. Based on these characteristics, these isolates showed a potential to be utilized in producing extracellular proteases that can be used in industrial processes such as the detergent industry which requires alkaline proteases, and leather tanning which requires proteases (keratinase) that are resistant to moderate salinity conditions.