The selection of alkaline protease-producing yeasts fi＇om marine environments and evaluation of their bioactive peptide production

• Published in: Chinese journal of oceanology and limnology Vol. 27; no. 4; pp. 753 - 761
• Main Author: 李静 池振明 王祥红 彭莹 池哲
• Format: Journal Article
• Language: English
• Published: 2009
• Subjects: 南美白对虾; 海洋环境; 生物活性肽; 碱性蛋白酶; 蛋白酶活性; 酵母培养; 金黄色葡萄球菌
• ISSN: 0254-4059

A total of 400 yeast strains from seawater, sediments, saltern mud, marine fish guts, and marine algae were obtained. The protease activity of the yeast cultures was estimated, after which four strains （HN3.11, Nllb, YF04C and HN4.9） capable of secreting extracellular alkaline protease were isolated. The isolated strains were identified as Aureobasidium pullulans, Yarrowia lipolytica, lssatchenkia orientalis and Cryptococcus cf. aureus. The optimal pH of the protease activity produced by strains HN3.11, YF04C, and HN4.9 was 9.0, while that of the protease produced by strain N1 lb was 10.0. The optimal temperature for protease activity was 45℃for strains HN3.11, N11b, and YF04C, and 50℃ for strain HN4.9. After digestion of shrimp （Penaeus vannamei） protein and spirulina （Arthospira platens＆） protein with the four crude alkaline proteases, the filtrate from spirulina （Arthrospira platensis） powder digested by the crude alkaline protease of strain HNYl 1 was found to have the highest antioxidant activity （61.4%） and the highest angiotensin I converting enzyme （ACE）-inhibitory activities （68.4%）. The other filtrates had much lower antioxidant activity and ACE-inhibitory activities.