| Acrylamide is a fine chemical product which was widely used.Compared with the traditional immobilized cells bioconversion process , the new technology of bioconversion coupled with the membrane separation had possessed many advantages as follow:process simplification,low cost,high utilization ratio of cells and free from contamination etc.To further promote the industrial productivity of acrylamide,the culture techniques of Rhodococcus sp.HUST-2 strain were improved in the prior period of our study , and a new technology of bioconversion coupled with the ultrafiltration membrane separation , in which a hollow-fiber membrane bioreactor was designed and the free cells were used as biocatalysts in the microbial bioconversion of acrylonitrile to acrylamide,was presented to replace the traditional technology.Firstly , by investigating the disciplinarian of enzyme production in fermentation procedures,the cultural conditions for the growth of Rhodococcus cells were optimized,including the controlling of pH value and the designing of supplemental scheme of glucose and inducer.By the above improvement the activity of nitrile hydratase (NHase) reached over 4000 U/ml,and the special enzyme activity of NHase reached 224.7U/mg (DCW),which were much higher than that in today's industry.Then,after the performance test and evaluation of membrane material,which included interception , membrane flux , anti-pollution and anti-swelling,the polysulfone hollow-fiber ultrafiltration membrane was chosen to be the material of membrane module.The membrane module was serially connected to the bioreactor,it was proved that the new process has many advantages such as easy operation , simple composition and easy cleaning . Mathematic module , optimization design and calculation were carried out for the membrane module from the point of view of hydraulics,this has shown directive significance of membrane design in industrial production process.Finally,two different operation modes were simultaneously developed,i.e. single-stage un-steady operation,single-stage false-steady operation, based on the new technology platform of bioconversion system coupling with the membrane separation and the feasibility of these operation modes were confirmed in lab-scale.The results showed that the two operation modes had their respective characteristics and had possessed many advantages compared with the traditional operation modes in productivity effect and utilization ratio of cells etc.In single-stage un-steady process,we developed and designed three kinds of different reaction batch single-stage un-steady processes according to different demands of product concentration.All the productivity effects had exceeded 0.02mol/L/min and the highest utilization ratio of cells was 0.7 gAM/mg in the process of 6-batches reaction.This single-stage un-steady process will be the ideal choice in miniature industrial production of acrylamide by right of its succinct technology and convenient operation.In single-stage false-steady process,optimization designs were carried out for the process in two ways of reaction temperature and the adding mode of cells.We found that productivity effect and utilization ratio of cells had raised tremendously,if the process was performed t at 20℃and the suspension was added into the reaction system by keeping continuous-flow adding mode.At last,this single-stage false-steady process was taken into application,the whole process had lasted over 20 hours,reaction rate was kept steady and a high product concentration of 313.1 g/L could be achieved.This kind of process will be fit for the large scale industrial production of acrylamide.
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