Earticle

Firstly, through the analysis of traditional processing mode of jewelry industry, the reason that influences or restricts the production and development of enterprises is obtained. Combined with the practical experience in scientific research, a production model taking computer technology as the core is proposed, and then the proposed model is compared with the traditional model on the advantages and tested in practical production, and achieved certain results. This study combines the computer aided design and rapid prototyping technology in the fields of computer technology with actual production requirement, and realizes the "concurrent engineering" from the "product development" to "product promotion", further to "product production" in jewelry industry chain, improving the production efficiency and achieving diversity development of business.

The thermal stability and catalytic activity of phospholipase A$_1$ from Serratia sp. MK1 were improved by an evolutionary molecular engineering. Two thermostable mutants were isolated after sequential rounds of error-prone PCR to introduce random mutations and filter-based screening of the resultant mutant library, and identified as having six (mutant TA3) and seven (mutant TA13) amino acid substitutions, respectively. Different types of the substitutions were found in two mutants, resulting in the increase of nonploar residues (mutant TA3) or changes between side chains within polar or charged residues (mutant TA13). The wild-type and mutant enzymes were purified, and the effect of temperature on their stability and catalytic activity was investigated. The T$\sub$m/ values of TA3 and TA13 were increased by 7 and 11$^{\circ}C$, respectively. Thus, evolutionary molecular engineering was found to be an effective and efficient approach to increasing thermostability without compromising enzyme activity.