Mutagenesis and characterization of a Bacillus amyloliquefaciens strain for Cinnamomum camphora seed kernel oil extraction by aqueous enzymatic method

• Published in: AMB Express Vol. 7; no. 1; pp. 154 - 10
• Main Authors: Zeng, Cheng, Zhao, Rongbin, Ma, Maomao, Zeng, Zheling, Gong, Deming
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 17.07.2017; Springer Nature B.V; SpringerOpen
• Subjects: Amylases; Aqueous enzymatic method; Bacillus amyloliquefacien; Biomedical and Life Sciences; Biotechnology; Calcium; Cellulase; Copper; Enzymatic properties; Enzymes; Extracellular enzymes; Extraction; Glucoamylase; Guanidine; Iron; Irradiation; Life Sciences; Microbial Genetics and Genomics; Microbiology; Milk; Mutagenesis; Oils & fats; Original; Original Article; Pectinase; Proteinase; Skim milk; Temperature effects; Ultraviolet radiation; UV and NTG mutation; UV and NTG mutation; Aqueous enzymatic method; Proteinase; Enzymatic properties; Bacillus amyloliquefacien
• ISSN: 2191-0855; 2191-0855
• DOI: 10.1186/s13568-017-0451-9

The purpose of the present study was to increase the proteinase activity of the strain NCU116 by combining ultraviolet irradiation and N -methyl- N′ -nitro- N -nitroso guanidine treatment, in order to enhance the efficiency of Cinnamomum camphora seed kernel oil (CCSKO) extraction by aqueous enzymatic method (AEM). The mutated strain, designated as NCU116-1, was screened out by the ratio of hydrolytic zone diameter to colony diameter on skim milk plate. The proteinase activity (9116.1 U/ml) of NCU116-1 was increased by 31.9% compared with the parental strain. The extracellular enzymes produced by NCU116-1 included proteinase, pectase, glucoamylase, cellulase and amylase. The proteinase had the maximum activity at 50 °C. Its optimum temperature and pH value were approximately 45 °C and 8.0 respectively. Mn 2+ was an activator of neutral proteinase. The glucoamylase had the maximum activity at 35 °C, and was activated by Cu 2+ , Fe 3+ and Mn 2+ . Its optimum temperatures and pH value were 35 °C and 8.0 respectively. The pectinase had the maximum activity at 40 °C, and was activated by Ca 2+ and Mn 2+ . Its optimum temperatures and pH value were 35–40 °C and 6.0 respectively. The optimum conditions of CCSKO extraction by AEM were also investigated. The results suggested that the best amount of enzyme solution and enzymolysis time were 20% (v/v) and 4 h, respectively. The oil extraction rate was 95.2% under these conditions. Thus, a suitable mutated strain was selected for CCSKO extraction by AEM and the optimum extraction conditions were determined.