ผลของการเสริมน้ำตาลต่อการผลิตสารลดแรงตึงผิวชีวภาพโดย Pichia anomala PY1 และลักษณะของสารที่ได้

Abstract

The highest efficiency for biosurfactant production by Pichia anomala strain PY1 was found in modified medium consist KH2PO4 0.02%, MgSO4.7H2O 0.02%, NaNO3 0.4%, yeast extract 0.3%, soybean oil 10.67% and glucose 5.33% with initial pH of 5.0. The cultivation was performed at 30oC in shake flask at 200 rpm. After 7 days of cultivation the biosurfactant produced possessed minimum surface tension of 33 mN/m, the critical micelle concentration (CMC) of 132 mg/l, oil displacement activity of 75.39 cm2 and yield of 0.95 g/l. The biochemical studies of the product obtained revealed that this biosurfactant has optimum pH and pH stability at pH 8.0. The same product was stabilized to temperature up to 121oC and could tolerated NaCl at 0.5-5.0%. In addition to could formed emulsion with oil and various hydrocarbon including canola oil, sesame oil, salad oil, rice bran oil, safflower oil, soybean oil, isopropyl myristate, n-hexadecane, and ethyl oleate etc. Analysis via analytical TLC showed 3 major peaks with Rf of 0.88, 0.72 and 0.62 (F1-F3) respectively. Among this F2 gave highest oil displacement activity and upon further purification by preparative TLC and high performance liquid chromatography a sery of peaks belong to F2 were isolated with molecular mass of 662 702 and 762 as indicated by their LC-MS spectrum correspond to sophorolipid compound containing fatty acid of [C22] Lactone and [C22:1]Lactone Department: