Alkaline serine protease produced from citric acid by Bacillus alcalophilus subsp. halodurans KP 1239

Abstract

Maximum production of alkaline serine protease by Bacillus alcalophilus subsp. halodurans KP 1239 was achieved after 24 h cultivation, at an initial pH of 7.6, on a medium containing 1.0% sodium citrate, 0.3% yeast extract, and 0.3% KH2PO4. The enzyme was purified to crystalline form from culture broth. The enzyme was most active at 60 degrees C and at pH 11.5. The molecular weight, isoelectric point and sedimentation coefficient in water at 20 degrees C were estimated as 29,000, 8.8 and 3.3S, respectively. The N-terminal amino acid sequence was Ala-Gln-Ser-Val-Pro-Trp-Gly-Ile-Ser-Arg-Val-Gln-Ala-Pro-Ala-Ala- His-Asn-Arg-Gly-. The enzyme shared its antigenic determinants with B. alcalophilus ATCC 21522 serine protease, but not with the subtilisins Carlsberg and BPN'.

Purification and characterization of halo-alkali-thermophilic protease from Halobacterium sp. strain HP25 isolated from raw salt, Lake Qarun, Fayoum, Egypt

“…The K m value of the purified halophilic protease towards casein was 523 µg mL −1 . This result is comparable to the results of Juhasz and Skarka (1990), Takii et al (1990) and Mesbah and Wiegel (2014), who reported that proteases with low K m values (400 and 1300 µg mL −1 ) towards casein substrate were produced by Bacillus alkalophilus, Brevibacterium linens and Alkalibacillus sp. NM-Fa4, respectively.…”

Production of Extracellular Halo-alkaline Protease from a Newly Isolated Haloalkaliphilic Bacillus sp. Isolated from Seawater in Western India

“…Similar studies on growth kinetics were also carried out with Bacillus sp. and other haloalkaliphilic organisms (Takii et al 1990;Ferrero et al 1996;Studdert et al 1997). In case of Aspergillus flavus, maximum enzyme production was obtained during the stationary phase.…”

Purification and characterization of a salt, solvent, detergent and bleach tolerant protease from a new gamma-Proteobacterium isolated from the marine environment of the Sundarbans

“…Merkel and Sipos [42] reported a protease from marine Vibrio, the temperature optima of which shifted from 40 to 50 8C in presence of 10 À3 M Ca 2+ ion. Better thermostability and enhancement of activity of our protease in the presence of Ca 2+ may possibly be a general effect of stabilizing as well as increasing the activity of serine proteases, mostly derived from Bacillus species [43][44][45][46][47]. As regards inhibition of protease activity by heavy metals, a review of literature shows that certain bacterial serine proteases are repressed by Zn 2+ , Hg 2+ and Cu 2+ while others are not.…”