Using acetone oxime and hydrochloric acid as raw materials,the hydrolysis of acetone oxime was carried out to prepare hydroxylamine hydrochloride. A quantitative analysis method by combining HPLC detection and redox titration was set up for the analysis of the reversible hydrolysis reaction equilibrium. The obtained analysis data of the combined method had a recovery of 99.64%and a RSD of no more than 2.04% (n=6). After that,a reactive distillation device was set up for the hydrolysis of acetone oxime,and the process technology of the reactive distillation was studied and optimized. The result showed that,at condition when the molar ratio of acetone oxime to HCl=1∶2, HCl mass fraction at 38%,heating temperature at 130℃ and reaction time at 3h,the raw material conversion of acetone oxime approached around 89% and the product yield of hydroxylamine hydrochloride reached about 84%.

The production of carboxylic acids and their derivatives which are hydrolyzed from nitrile by nitrile-hydrolyzing enzyme(nitrilase or nitrile hydratase/amidase) have been widely used in pharmaceutical.In order to obtain more nitrile-hydrolyzing enzymes(nitrilase or nitrile hydratase/amidase),it is very important to build a high-throughput screening strategy.In this paper,a modified ferric hydroxamate spectrophotometry was established,which is simple,rapid,and high-throughput.The accuracy of the method established was validated by the bioconversion of nitrile hydrolysis with the resting cells of Rhodococcus sp.CCZU10-1.The results indicate that the accuracy of this method for assaying carboxylic acids is as high as the HPLC-based method.Therefore,the method established can be used for the screening and application of microorganisms with nitrile-hydrolyzing activity.

A high-throughput screening method for nitrile-hydrolyzing enzyme was used based on a modified ferric hydroxamate spectrophotometry.Using 3-cyanopyridine as a sole nitrogen source,a nitrile-hydrolyzing strain was isolated from soil.It was identified as Rhodococcus sp.by 16S rDNA sequence analysis.Moreover,the optimum reaction temperature,pH and metal ion additive were 30 ℃,7.0 and Ca2+(0.1 mmol/L),respectively.After 36 h of biotransformation,the yield of nicotinic acid from the hydrolysis of 3-cyanopyridine(50 mmol/L) reached 93.5%.