title: Enhancement of thermostable lipase production by a genotypically identified extremophilic Bacillus subtilis NS 8 in a continuous bioreactor.
abstract: Bacillus strain NS 8, a lipase-producing bacterium isolated from a Malaysian hot spring, is able to tolerate a broad range of temperature and pH, which makes it beneficial for this study. It generated PCR products with molecular weight of 1,532 bp, and the 16S rRNA sequence analysis identified it as Bacillus subtilis with accession number AB110598. It showed a 71% similarity index with B. subtilis using Biolog Microstation System. Its lipase production was optimized using a shake flask system by changing the physical (agitation speed, pH and temperature) and nutritional (nitrogen, carbon and minerals) factors. The most suitable combination of the basal medium for lipase production was 2.5% olive oil (carbon), 1.5% peptone (nitrogen), 0.1% MgSO(4) (mineral) at an optimum temperature of 50°C, pH 7.5 and 150 rpm agitation, giving an enzyme yield of 4.23 U/ml. Statistical optimization using response surface methodology was carried out. An optimum lipase production of 5.67 U/ml was achieved when olive oil concentration of 3%, peptone 2%, MgSO(4)·7H(2)O 0.2% and an agitation rate of 200 rpm were combined. Lipase production was further carried out inside a 2-liter bioreactor, which yielded an enzyme activity of 14.5 U/ml after 15 h of incubation.
authors.affiliation: Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang, Malaysia.
authors.forename: Akanbi Taiwo
authors.initials: AT
authors.lastname: Olusesan
authors.forename: L Kamaruzaman
authors.initials: LK
authors.lastname: Azura
authors.forename: Fatimah
authors.initials: F
authors.lastname: Abubakar
authors.forename: Abdul Karim Sabo
authors.initials: AK
authors.lastname: Mohamed
authors.forename: Son
authors.initials: S
authors.lastname: Radu
authors.forename: Mohd Yazid Abdul
authors.initials: MY
authors.lastname: Manap
authors.forename: Nazamid
authors.initials: N
authors.lastname: Saari
mesh_terms: D001412:Bacillus subtilis / Q000145:classification / Q000201:enzymology* / Q000254:growth & development* / Q000302:isolation & purification; D001426:Bacterial Proteins; D015373:Bacterial Typing Techniques; D001483:Base Sequence; D019149:Bioreactors; D016000:Cluster Analysis; D003470:Culture Media / Q000737:chemistry; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D045482:Hot Springs / Q000382:microbiology; D006358:Hot Temperature; D008049:Lipase / Q000378:metabolism*; D008296:Malaysia; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D008049:Lipase; C428386:thermostable lipase