Alpha-amylase (E.C. 3.2.1.1) is an enzyme that catalyzes the hydrolysis of α-1,4 linkages in starch and related carbohydrates and has been widely applied in starch processing, baking, brewing and the de-sizing of textiles [1][2][3]. In industrial starch processing, α-amylases are used in the liquefaction step to hydrolyze starch into glucose oligomers. The ideal temperature and pH for this step are 105 o C and pH 4.5, respectively. Since 1980, Bacillus licheniformis α-amylase has been the main enzyme used in starch liquefaction. This enzyme exhibits optimal activity at 90 o C and pH 6.0, which can only partly satisfy the starch liquefaction requirement [4][5][6]. Hyperthermophilic enzymes exhibit optimal activity at temperatures higher than 90 o C. Most of these enzymes come from thermophilic archaea, like Pyrococcus furiosus, Thermococcus kodakarensis and Sulfolobus solfataricus, while the remainder come from thermophilic bacteria [7][8][9]. P. furiosus α-amylase is a hyperthermophilic enzyme that exhibits optimal activity at about 100 o C, where it has a half-life of more than 12 h [10,11]. In addition to its excellent thermostability, P. furiosus α-amylase exhibits optimal activity at a pH of about 5.6, with good stability and no less than 80% of optimal activity at pH values from 4.5 to 6.5. These characteristics make P. furiosus α-amylase potentially suitable for industrial applications.P. furiosus α-amylase has been known and characterized since 1990, but the relatively low level of heterologous expression has limited its industrial application [2]. When produced in Escherichia coli, P. furiosus α-amylase is Pyrococcus furiosus α-amylase can hydrolyze α-1,4 linkages in starch and related carbohydrates under hyperthermophilic condition (~ 100°C), showing great potential in a wide range of industrial applications, while its relatively low productivity from heterologous hosts has limited the industrial applications. Bacillus subtilis, a gram-positive bacterium, has been widely used in industrial production for its non-pathogenic and powerful secretory characteristics. This study was conducted to increase production of P. furiosus α-amylase in B. subtilis through three strategies. Initial experiments showed that co-expression of P. furiosus molecular chaperone peptidyl-prolyl cis-trans isomerase through genomic integration mode, using a CRISPR/Cas9 system, increased soluble amylase production. Therefore, considering that native P. furiosus α-amylase is produced within a hyperthermophilic environment and is highly thermostable, heat treatment of intact culture at 90 o C for 15 min was performed, thereby greatly increasing soluble amylase production. After optimization of the culture conditions (nitrogen source, carbon source, metal ion, temperature and pH), experiments in a 3-L fermenter yielded a soluble activity of 3,806.7 U/ml, which was 3.3-and 28.2-fold those of a control without heat treatment (1,155.1 U/ml) and an empty expression vector control (135.1 U/ml), respectively. This represents the highest P. f...

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The sudden outbreak of the pandemic COVID-19 inevitably has a great impact on economic and social development. Therefore, the innovation-driven value becomes more and more prominent. Through literature review, it is not difficult to find that values have gradually become an important reference standard for organizations to select talents for their teams, as well as an important reference factor for studying organizational citizenship behavior. In order to explore the relationship between values realization degree and organizational citizenship behavior, this investigation based on the social interaction theory was conducting using a sample of enterprise staff (N=358). In this paper, LISRELV9.2 and SPSS21.0 were used to analyze the sample data, including descriptive statistical analysis, common variance deviation test, reliability and validity test, one-way ANOVA, correlation analysis, regression analysis, and validation of mediating effects. The results showed that values realization degree positively predicted organizational citizenship behavior, and job satisfaction played an intermediary role in the relationship between values realization degree and organizational citizenship behavior. Besides, there were some differences between the relation that work values realization degree and organizational citizenship behavior acted on organizational citizenship behavior.

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