TITLE:
Characterization of Lipases from Geobacillus stearothermophilus and Anoxybacillus flavithermuscell Lysates
AUTHORS:
Teif A. Najm, Marie K. Walsh
KEYWORDS:
Geobacillus, Anoxybacillus, Thermostable, Lipase
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.13 No.3,
March
17,
2022
ABSTRACT: The aim of this study was to characterize lipases from two thermophilic
bacteria, Geobacillus stearothermophilus (GS) and Anoxybacillus flavithermus (AF) in heat treated cell lysates. The pH optimum, pH stability,
temperature stability and substrate kinetics and
specificity of the lipases were determined. Optimum activity of the lipase from GS (LGS) was observed at pH 7.5, and the
optimum activity of the lipase from AF (LAF) was at pH 8.0. LGS was stable up
to 70°C after 12 hrs while LAF was stable up to 90°C after 12 hrs. Both enzymes were stable at a
pH range of 6 to 8 over 12 h at 4°C. LGS had a highest Vmax value of 22 mM·min-1·mg-1 with p-nitrophenyl acetate while the lowest Km was 0.8 mM with p-nitrophenyl laurate. The highest Vmax of LAF was 2.5 mM·min-1·mg-1 with p-nitrophenyl myristate, and the lowest Km was 0.4 mM with p-nitrophenyl octanoate. LGS preferentially hydrolyzed
p-nitrophenyl acetate and p-nitrophenyl octanoate while LAF preferentially
hydrolyzed p-nitrophenyl myristate and p-nitrophenyldodecanoate. Lipases from
both GS and AF showed characteristics that would be beneficial in food
processing.