Biochemical characterization of a novel lipase from Malbranchea cinnamomea suitable for production of lipolyzed milkfat flavor and biodegradation of phthalate esters

摘要

A novel lipase gene (McLipB) was cloned from a thermophilic fungus Malbranchea cinnamomea and expressed in Pichia pastoris. The deduced amino acid sequence of the lipase (McLipB) shared the highest identity of 46% with the Candida rugosa lipase LIP4. The extracellular lipase activity of 4304 U/mL with protein concentration of 7.7 mg/mL was achieved in a 5-L fermentor. The optimal pH and temperature of McLipB were 7.5 and 40 degrees C, respectively. The lipase showed high specificity towards triglycerides with short and medium chain fatty acids, and had non-position specificity. McLipB hydrolyzed butter to produce mainly butyric acid, hexanoic acid and a small amount of octanoic acid and decanoic acid. Furthermore, it degraded more than 90% dipropyl phthalate, dibutyl phthalate and dihexyl phthalate to their corresponding monoalkyl phthalates. The properties of McLipB indicate that it has great application potential for production of lipolyzed milkfat flavor and biodegradation of phthalate esters.