选取3种方式对淀粉活化预处理,以活化淀粉和苯甲酰氯为原料,制备苯甲酸淀粉酯,结果表明,酶解淀粉酯化产物取代度最高。确定了最佳合成条件:活化淀粉用量2.0 g,苯甲酰氯用量3.0 m L,吡啶用量2.0 m L,反应温度55℃,反应时间5 h。此条件下...选取3种方式对淀粉活化预处理,以活化淀粉和苯甲酰氯为原料,制备苯甲酸淀粉酯,结果表明,酶解淀粉酯化产物取代度最高。确定了最佳合成条件:活化淀粉用量2.0 g,苯甲酰氯用量3.0 m L,吡啶用量2.0 m L,反应温度55℃,反应时间5 h。此条件下,苯甲酸淀粉酯的取代度达0.289 8。展开更多
In order to enrich the degrading microbial resources for phthalic acid esters(PAEs)under cadmium stress,a degrading bacterium B-7 for di(2-ethylhexyl)phthalate(DEHP)was screened from the strains stored in the laborato...In order to enrich the degrading microbial resources for phthalic acid esters(PAEs)under cadmium stress,a degrading bacterium B-7 for di(2-ethylhexyl)phthalate(DEHP)was screened from the strains stored in the laboratory by means of inorganic salt liquid medium containing DEHP and cadmium,and the characteristics of the strain were studied.Strain B-7 was Bacillus amyloliquefaciens,which had high biosafety and excellent degradability to DEHP.The optimum temperature for degradation was 25–40℃,and the optimum pH value was 6–8.Strain B-7 was cultured in inorganic salt medium(MSM)with an initial DEHP concentration of 400 mg/L and cadmium content of 10 mmol/L for 4 d,and its degradation rate of DEHP was up to 93.1%.In addition,the strain had a strong degradation ability to dimethyl phthalate(DMP),diethyl phthalate(DEP),and dibutyl phthalate(DBP).In soil contaminated by cadmium and DEHP,the synergic degradation of B-7 and indigenous microorganisms in soil significantly increased the degradation rate of DEHP,indicating that this strain had potential application value in the field of microbial remediation of soil contaminated by cadmium and PAEs.展开更多
基金Supported by Natural Science Foundation of Hunan Province(2020JJ5321,2021JJ30412)。
文摘In order to enrich the degrading microbial resources for phthalic acid esters(PAEs)under cadmium stress,a degrading bacterium B-7 for di(2-ethylhexyl)phthalate(DEHP)was screened from the strains stored in the laboratory by means of inorganic salt liquid medium containing DEHP and cadmium,and the characteristics of the strain were studied.Strain B-7 was Bacillus amyloliquefaciens,which had high biosafety and excellent degradability to DEHP.The optimum temperature for degradation was 25–40℃,and the optimum pH value was 6–8.Strain B-7 was cultured in inorganic salt medium(MSM)with an initial DEHP concentration of 400 mg/L and cadmium content of 10 mmol/L for 4 d,and its degradation rate of DEHP was up to 93.1%.In addition,the strain had a strong degradation ability to dimethyl phthalate(DMP),diethyl phthalate(DEP),and dibutyl phthalate(DBP).In soil contaminated by cadmium and DEHP,the synergic degradation of B-7 and indigenous microorganisms in soil significantly increased the degradation rate of DEHP,indicating that this strain had potential application value in the field of microbial remediation of soil contaminated by cadmium and PAEs.
