Production and Biotechnological Application of Extracellular Alkalophilic Lipase from Marine Macroalga-Associated Shewanella algae to Produce Enriched C20-22 n-3 Polyunsaturated Fatty Acid Concentrate

Characterization of a New Thermostable and Organic Solution-Tolerant Lipase from Pseudomonas fluorescens and Its Application in the Enrichment of Polyunsaturated Fatty Acids

The search for and characterization of new lipases with excellent properties has always been urgent and is of great importance to meet industrial needs. In this study, a new lipase, lipB, from Pseudomonas fluorescens SBW25, belonging to the lipase subfamily I.3, was cloned and expressed in Bacillus subtilis WB800N. Enzymatic properties studies of recombinant LipB found that it exhibited the highest activity towards p-nitrophenyl caprylate at 40 °C and pH 8.0, retaining 73% of its original activity after incubation at 70 °C for 6 h. In addition, Ca²⁺, Mg²⁺, and Ba²⁺ strongly enhanced the activity of LipB, while Cu²⁺, Zn²⁺, Mn²⁺, and CTAB showed an inhibiting effect. The LipB also displayed noticeable tolerance to organic solvents, especially acetonitrile, isopropanol, acetone, and DMSO. Moreover, LipB was applied to the enrichment of polyunsaturated fatty acids from fish oil. After hydrolyzing for 24 h, it could increase the contents of polyunsaturated fatty acids from 43.16% to 72.18%, consisting of 5.75% eicosapentaenoic acid, 19.57% docosapentaenoic acid, and 46.86% docosahexaenoic acid, respectively. The properties of LipB render it great potential in industrial applications, especially in health food production.

Production and characterization of psychrophilic α-amylase from a psychrophilic bacterium, Shewanella sp. ISTPL2

A psychrophilic and halophilic bacterial isolate, Shewanella sp. ISTPL2, procured from the pristine Pangong Lake, Ladakh, Jammu and Kashmir, India, was used for the production and characterization of the psychrophilic and alkalophilic α-amylase enzyme. The α-amylase is a critical enzyme that catalyses the hydrolysis of α-1,4-glycosidic bonds of starch molecules and is predominately utilized in biotechnological applications. The highest enzyme activity of partially purified extracellular α-amylase was 10,064.20 U/mL after 12 h of incubation in a shake flask at pH 6.9 and 10 °C. Moreover, the maximum intracellular α-amylase enzyme activity (259.62 U/mL) was also observed at 6 h of incubation. The extracellular α-amylase was refined to the homogeneity with the specific enzyme activity of 36,690.47 U/mg protein corresponding to 6.87-fold purification. The optimized pH and temperature for the α-amylase were found to be pH 8 and 4 °C, respectively, suggesting its stability at alkaline conditions and low or higher temperatures. The amylase activity was highly activated by Cu2+, Fe2+ and Ca2+, while inhibited by Cd2+, Co2+ and Na2+. As per our knowledge, the current study reports the highest activity of a psychrophilic α-amylase enzyme providing prominent biotechnological potential.