摘要
Polylactide is regarded as the most promising biodegradable plastics because of its high quality in physical properties as well as chemical recyclability and compostabil-ity. Furthermore, lactic acid (LA) as a raw material of this polymer can be produced from organic wastes. In this study, recovery LA from fermentation broth of kitchen garbage was carried out by esterification of ammonium lactate in fer-mentation broth with the butanol to produce butyl lactate, purification of butyl lactate and subsequent hydrolysis of the purified butyl lactate. The purity of recovered LA was 90%. Then the recovered LA was used to produce lactide as an intermediate of polylactide. Through an orthogonal-design experiment, the optimum condition of synthesizing lactide was determined and under this condition the yield of synthe-sizing lactide was 75%. And moreover, polylactide was con-ventionally obtained by a ring-opening polymerazation from the above lactide, and the viscosity average molecular weight was up to 9.2×104, which could meet requirement to produce biodegradable plastics. In the present process, the neutral ammonium lactate in the fermentation broth was employed as a starting material, thereby eliminating the need to use a reactor with acid resistance properties. In addition, the lib-erated butanol in hydrolysis process and unreacted butanol in esterification process can be recycled to the above esterifi-cation. Therefore, the present process is economic.
Polylactide is regarded as the most promising biodegradable plastics becauseof its high quality in physical properties as well as chemical recyclability and compostability.Furthermore, lactic acid (LA) as a raw material of this polymer can be produced from organic wastes.In this study, recovery LA from fermentation broth of kitchen garbage was carried out byesterification of ammonium lactate in fermentation broth with the butanol to produce butyl lactate,purification of butyl lactate and subsequent hydrolysis of the purified butyl lactate. The purity ofrecovered LA was 90 percent, Then the recovered LA was used to produce lactide as an intermediateof polylactide. Through an orthogonal-design experiment, the optimum condition of synthesizinglactide was determined and under this condition the yield of synthesizing lactide was 75 percent,And moreover, polylactide was conventionally obtained by a ring-opening polymerazation from theabove lactide, and the viscosity average molecular weight was up to 9.2x10^4, which could meetrequirement to produce biodegradable plastics. la the present process, the neutral ammonium lactatein the fermentation broth was employed reactor with acid resistance properties. In addition, theliberated butanol in hydrolysis process and unreacted butanol in esterification process can berecycled to the above esterification. Therefore, the present process is economic.
基金
supported by the National Natural Science Foundation of China(Grant No.50278024)
the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Heilongjiang Province(Grant No.LC02C03).
关键词
厨房垃圾
聚交酯
乳酸菌
丙交酯
kitchen garbage
lactic acid fermentation
butyl lactate
lactide
polylactide
