Preparation And Application Of Porous Corn Starch

Natural corn starch(CS)has been widely used in food,chemical industry,medicine and other fields because of its low cost and unique physical and chemical properties.In order to improve the application value of corn starch,porous corn starch(PCS)was prepared and applied.The most common preparation method is to use commercial enzyme to prepare porous corn starch,but the commercial enzyme needs the starch to reach the gelatinization temperature to carry out enzymatic hydrolysis in the use process,while Aspergillus niger can secrete starch powder enzyme to carry out enzymatic hydrolysis without making the starch reach the gelatinization temperature when using Aspergillus niger fermentation method to prepare porous corn starch,and enzyme production and pore preparation can be carried out simultaneously.In this paper,PCS was prepared by Aspergillus niger fermentation,and then assembled into model drug Rhodamine B(Rh B),anti-tumor drug Tamoxifen Citrate(TAM)and anti-inflammatory drug Ibuprofen(IBU).Magnetic porous corn starch(MPCS)was prepared by magnetic PCS,and the adsorption of livestock wastewater was studied.Firstly,the optimal conditions of PCS production by Aspergillus niger fermentation were selected by single-factor orthogonal experiment and response surface methodology with the oil absorption of PCS as the index.The results showed that the oil absorption rate of PCS was 128% under the following conditions: p H=7,temperature 28℃,inoculation amount 7%,prophase fermentation 40 h,anaphase fermentation 56 h,starch addition amount 7%.The biocompatibility of PCS to human epidermal fibroblast(HSF)and human breast cancer cell line(MCF-7)was investigated by MTT assay.The results showed that PCS had no obvious cytotoxicity to the two kinds of cells.Then,Rh B,TAM and IBU were assembled and sustained-released from PCS by liquid impregnation method.The results showed that when the concentration of the three drugs was 500 mg/L and the dosage of PCS was 0.1 g,the assembly amount of PCS to Rh B,TAM and IBU was 46.74 mg/g,33.78 mg/g and 32.56 mg/g,respectively.The cumulative release rates of Rh B@PCS,TAM@PCS and IBU@PCS were 96.8%,94.88% and 93.14%,respectively.The cumulative release rates in PBS were 93.3%,90.14% and 89.62%,respectively.The inhibitory effect of TAM@PCS on the proliferation of breast cancer cells(MCF-7)in vitro increased with the increase of sustained release time.The antibacterial effect of IBU@PCS against E.coli increased gradually with the increase of sustained release time.It was further verified that TAM@PCS and IBU@PCS had good sustained release effect.Finally,MPCS was used to treat livestock wastewater.After 0.1 g MPCS was used to treat 50 m L wastewater diluted 40 times for 420 min,the total nitrogen,total phosphorus and chemical oxygen demand in the wastewater were reduced to 15.02mg/L,0.29 mg/L and 102 mg/L,respectively,and the effective removal rates were55.23%,85.01% and 58%,respectively.The phytotoxicity test of the treated wastewater showed that there was no obvious phytotoxicity in the livestock wastewater treated by MPCS.