Gene cloning and expression of the L-asparaginase from Bacillus cereus BDRD-ST26 in Bacillus subtilis WB600

L-Asparaginase (ASN; EC 3.5.1.1) shows great commercial value because of its ability to reduce toxic levels of acrylamide in foods. To achieve high -efficiency production of L-asparaginase, an open reading frame of 978 bp encoding asparaginase (BcA) was amplified from Bacillus cereus BDRD-ST26, followed by its expression in Bacillus subtilis WB600, with the highest yield of 374.9 U/ml obtained using an amyE-signal peptide. A four -step purification protocol was used to purify BcA, resulting in a 15.1 -fold increase in purification yield, with a specific activity of purified BcA at 550.8 U/mg and accompanied by detection of minimal L-glutaminase activity. Maximum BcA activity was detected at 50 degrees C and pH 9.0 in 20 mM Tris HCI buffer, with a half-life at 50 degrees C of 17.35 min and a Km and kcat of 9.38 mM and 63.6 s(-1), respectively. Compared with untreated potato strips, 72% acrylamide (2.35 mg/kg) was removed from potato strips pretreated with BcA. These results indicated that this novel BcA variant represents a potential candidate for application in the food processing industry. (C) 2018, The Society for Biotechnology, Japan. All rights reserved.