Isolation and characterization of novel thermophilic lipase-secreting bacteria

Rabbani, MohammedReza Bagherinejad, MohammadMirMohammad Sadeghi, HamidSamsam Shariat, ZiaedinEtemadifar, ZahraMoazen, FatemehRahbari, ManizhehMafakher, LadanZaghian, Saeideh

The purpose of the present study was to screen and identify the lipase-producing microorganisms from various regions of Iran. Samples collected from hot spring, Persian Gulf, desert area and oil-contaminated soil, were analyzed for thermophilic extracellular-lipase producing organisms. Six strains with high activity on rhodamine B plates were selected for chemical identification and further study. Among these isolated bacteria, four strains show higher activity in pH-Stat method at 55 °C. These strains were identified by PCR amplification of 16s rRNA genes using universal primers. Fermentation increased the activity up to 50%. The growth medium, designed for lipase production, increased the activity up to 4.55 folds. The crude supernatant of ZR-5 after fermentation and separation the cells, was lyophilized and the activity was measured. Total activity of this strain was 12 kU/g that shows its potential for industrial uses. Further study is required for purification of enzyme and calculation its specific activity. Immobilization is another approach should be considered.

1. fermentation
2. thermophilic lipase
3. extracellular lipase
4. pH-stat method