3MP组分可控的共聚酯P(3MP-co-3HB)体外合成及产物性质分析

In vitro synthesis and product property analysis of copolyester P(3MP-co-3HB)with controllable 3MP components

[目的]以3-巯基丙酸(3MP)作为第二组分,利用设计的单相反应体系实现共聚酯P(3MP-co-3HB)中3MP组分的可控合成,并分析3MP组分掺入对聚羟基丁酸酯(PHB)性质的影响。[方法]根据设计的P(3MP-co-3HB)体外合成途径,利用体外重组表达纯化的乙酰辅酶A合成酶(ACSPt)、CoA转移酶(PCT_(Cp))、PHA合酶(PhaCRe)作为催化剂,以不同摩尔比的(R)-3-羟基丁酸[(R)-3HB]和3MP作为底物,合成共聚物P(3MP-co-3HB)s。利用1H-NMR、GPC、DSC和TG等测试手段分析产物的结构与热性质。[结果]产物的1H-NMR结果表明,3MP∶3HB的摩尔比为0∶1、1∶3和1∶1时,分别合成PHB、P(55.4 mol%3MP-co-3HB)和P(70 mol%3MP-co-3HB),产量分别为2.00 g/L、0.72 g/L和0.26 g/L。产物的GPC结果表明,随着3MP摩尔组分的增加,共聚物的Mn由40.10 kDa增加至45.40 kDa,Mw由91.00 kDa增加至102.80 kDa,PDI在2.25~2.27范围。DSC、TG测试结果表明,P(55.4 mol%3MP-co-3HB)和P(70 mol%3MP-co-3HB)的Tm、Td分别为134.90℃、112.50℃和239.70℃、271.40℃。[结论]利用设计的OPRS可合成含高3MP摩尔比例的P(3MP-co-3HB)s,其3MP组分在0 mol%~70 mol%范围内可控。含有3MP组分的共聚酯能很好地改善PHB的加工性能。

[Objective]To achieve the controlled synthesis of 3MP component in copolyester P(3MP-co-3HB)using a designed Single-phase Reaction System with 3-mercaptopropionic acid(3MP)as the second component,and to analyze the effect of 3MP component incorporation on the properties of polyhydroxybutyrate(PHB).[Method]According to the designed in vitro synthesis pathway of P(3MP-co-3HB),the copolymer P(3MP-co-3HB)s were synthesized using in vitro recombinant expression of purified acetyl coenzyme A synthase(ACS_(Pt)),CoA transferase(PCT_(Cp)),and PHA synthase(PhaC_(Re))as catalysts with different molar ratios of(R)-3-hydroxybutyric acid[(R)-3HB]and 3MP as substrates.The structure and thermal properties of the products were analyzed using~1H-NMR,GPC,DSC and TG tests.[Result]The~1H-NMR results of the products showed that PHB,P(55.4 mol%3MP-co-3HB)and P(70 mol%3MP-co-3HB)were synthesized in yields of 2.00 g/L,0.72 g/L and 0.26 g/L,respectively,at molar ratios of 0∶1,1∶3 and 1∶1 of 3MP∶3HB.The GPC results of the products showed that the copolymer M_n increased from 40.10 kDa to 45.40 kDa,M_w increased from 91.00 kDa to 102.80 kDa and PDI was in the range of 2.25-2.27 as the molar fraction of 3MP increased.The results of DSC and TG tests showed that the T_m and T_d of P(55.4 mol%3MP-co-3HB)and P(70 mol%3MP-co-3HB)were 134.90℃,112.50℃and 239.70℃,271.40℃,respectively.[Conclusion]P(3MP-co-3HB)s containing a high 3MP molar ratio can be synthesized using the designed OPRS with a controllable 3MP fraction in the range of 0 mol%-70 mol%.The copolyesters containing 3MP fraction can improve the processing properties of PHB very well.