title: Approach toward enhancement of halophilic protease production byHalobacteriumsp. strain LBU50301 using statistical design response surface methodology.
abstract: A new potent halophilic protease producer,Halobacteriumsp. strain LBU50301 was isolated from salt-fermented fish samples (budu) and identified by phenotypic analysis, and 16S rDNA gene sequencing. Thereafter, sequential statistical strategy was used to optimize halophilic protease production fromHalobacteriumsp. strain LBU50301 by shake-flask fermentation. The classical one-factor-at-a-time (OFAT) approach determined gelatin was the best nitrogen source. Based on Plackett-Burman (PB) experimental design; gelatin, MgSO4·7H2O, NaCl and pH significantly influenced the halophilic protease production. Central composite design (CCD) determined the optimum level of medium components. Subsequently, an 8.78-fold increase in corresponding halophilic protease yield (156.22 U/mL) was obtained, compared with that produced in the original medium (17.80 U/mL). Validation experiments proved the adequacy and accuracy of model, and the results showed the predicted value agreed well with the experimental values. An overall 13-fold increase in halophilic protease yield was achieved using a 3 L laboratory fermenter and optimized medium (231.33 U/mL).
authors.affiliation: Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand.
authors.forename: Julalak
authors.initials: J
authors.lastname: Chuprom
authors.affiliation: Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand.
authors.forename: Preeyanuch
authors.initials: P
authors.lastname: Bovornreungroj
authors.affiliation: Institute of Nutrition (INMU), Mahidol University, 999 Phutthamonthon 4 Rd., Salaya, Nakhon Pathom 73170, Thailand.
authors.forename: Mehraj
authors.initials: M
authors.lastname: Ahmad
authors.affiliation: Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand.
authors.forename: Duangporn
authors.initials: D
authors.lastname: Kantachote
authors.affiliation: Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand.
authors.forename: Sawitree
authors.initials: S
authors.lastname: Dueramae
keywords: Gelatin; Halobacterium sp. strain; Halophilic protease; Response surface methodology