Identification of a GDSL lipase from Streptomyces bacillaris and its application in the preparation of free astaxanthin

[Display omitted] •OUC-Sb-lip12 is a novel GDSL lipase expressed in Bacillus subtilis WB 800.•B. subtilis can efficiently secrete lipase in 9 h, making mass production possible.•OUC-Sb-lip12 is a GDSL lipase with good thermostability and alkaline stability.•The hydrolysis of astaxanthin was conducted at 45 °C, preventing the growth of germs.•The hydrolysis rate of astaxanthin esters could reach 96.29% in 12 h. Astaxanthin shows multiple biological activities, but it is usually linked to different fatty acids and exists in the form of esters. The complexity of astaxanthin esters limits their application in the preparation of sophisticated drugs. Herein, a novel lipase from Streptomyces bacillaris that could hydrolyze astaxanthin esters, named OUC-Sb-lip12, was expressed in Bacillus subtilis. The active site of OUC-Sb-lip12 is probably composed of a dyad of Ser48 and His254, instead of a typical catalytic triad. The lipase was identified to be a GDSL hydrolase, and it showed highest activity at 45 °C and pH 9.0 (glycine-NaOH buffer). OUC-Sb-lip12 showed a good stability at its optimum temperature or a higher temperature, retaining 88.4% and 80.6% of its activity after incubating for 36 h at 45 °C and 55 °C, respectively. OUC-Sb-lip12 could effectively hydrolyze astaxanthin esters in Haematococcus pluvialis oil, generating free astaxanthin. Under the optimum conditions, 96.29% astaxanthin esters were hydrolyzed in 12 h. In addition, B.subtilis is a GRAS model strain and it could efficiently secrete lipase in 9 h, making the lipase potential for scale production of free astaxanthin, which could be further used in the preparation of specific astaxanthin esters with specific functions.