Isolation, identification and characterization of a novel elastase from Chryseobacterium indologenes

Abstract

Elastase is a type of protease that specifically degrades elastin. It has broad application prospects in medicine, food industry, and daily-use chemical industry. In this study, we isolated a bacterial strain WZE87 with high elastin-hydrolysis activity, which was identified as Chryseobacterium indologenes based on morphology, physiological and biochemical characteristics, and 16S rDNA sequence analysis. The elastase produced by this strain was purified by three steps: ammonium sulfate precipitation, Q-Sepharose fast-flow anion-exchange chromatography, and Sephadex G-75 gel-filtration chromatography. The purified elastase was 2376.5 U/mg in activity (a 8.3-fold increase in specific activity), and the recovery was 5.8%. Its molecular mass was estimated to be 26 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This enzyme was stable in the pH range of 5.0-10.5 at 37°C. The optimal temperature and pH were 37°C and 7.5, respectively. The activity of this elastase was found to decrease when the temperature was higher than 50°C. The activity was also inhibited by Zn 2? , Fe 2? , Fe 3? , and Mn 2? ions. The specific hydrolytic ability of this enzyme was similar to that of papain on substrates like gelatin, casein, soybean-isolated protein and bovine hemoglobin. However, this elastase preferentially hydrolyzed elastin in a protein mixture because of its specific adsorption. Considering its promising properties, this protease may be considered a potential candidate for applications in related industries.

A survey of elastase-producing bacteria and characteristics of the most potent producer, Priestia megaterium gasm32

“…(Fig 1). Among other investigators, a 34 kDa molecular mass was reported for an elastase from P. aeruginosa [35], a 26 kDa molecular mass was reported for an elastase from C. indologenes [3], and a 23.7 kDa molecular mass was reported for an elastase from the alkalophilic Bacillus strain Ya-B [25].…”

“…The pH stability of gasm32 elastase was observed at pH 6.0 to 10.0 for 2 hours (Fig 2 ). A wide pH stability spectrum was also observed for the elastase of C. indologenes (pH 5.0-10.5, [3]), the elastase of Flavobacterium odoratum (pH 5.0-10.0, [39]), and the serine-elastase of P. aeruginosa ZuhP13 (pH range of 6.0-9.0, [13]). The high alkaline character of gasm32 elastase revealed by its activity and stability over a wide pH range also suggests its suitability for use under alkaline conditions such as detergent additives.…”

“…Uttatree et al [31] isolated Bacillus megaterium from marine sediment in the Gulf of Thailand at a depth of 24 meters. Lei et al [3] isolated a novel elastase from Chryseobacterium indologenes from the mud of a meat market in Ya'an city. Elastase is expected to have potential application in meat tenderization because of its specific hydrolysis toward elastin.…”

“…Nonetheless, this source is insufficient to meet the needs of industry and daily use. Microorganisms can produce high levels of elastases [3].…”

“…The majority of microbial elastases are produced by Pseudomonas aeruginosa [7], Staphylococcus epidermidis [8], Bacillus licheniformis [5], Bacillus subtilis [9], and Chryseobacterium indologenes [3]. Unfortunately, most of them have low stability under environmental conditions.…”