Comparative evaluation of physico-chemical characteristics of biopolyesters P（3HB） and P（3HB-co-3HV） produced by endophytic Bacillus cereus RCL 02

作     者：Ritupama Das Nayan Ranjan Saha Arundhati Pal Dipankar Chattopadhyay Amal Kanti Paul 

作者机构：Microbiology Laboratory Department of Botany University of Calcutta 35 Ballygunge Circular Road Kolkata 700019 West Bengal India Department of Polymer Science and Technology University of Calcutta 92 A. P. C. Road KoIkata 700009 West Bengal India Department of Botany Serampore College 9 William Carey Road Serampore Hooghly 712201 West Bengal India 

出 版 物：《Frontiers in Biology》 (生物学前沿（英文版）)

年 卷 期：2018年第13卷第4期

页      面：297-308页

核心收录：

学科分类：0710[理学-生物学] 0831[工学-生物医学工程（可授工学、理学、医学学位）] 071001[理学-植物学] 0821[工学-纺织科学与工程] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 1001[医学-基础医学(可授医学、理学学位)] 07[理学] 08[工学] 0836[工学-生物工程] 082101[工学-纺织工程] 0713[理学-生态学] 

基　　金：Research support to Rituparna Das from the Department of Science and Technology, New Delhi, India support obtained from University Grants Commission (UGC), New Delhi, India 

主　　题：poly(3-hydroxybutyrate) poly(3-hydroxybutyrate-co-3-hydroxyvalerate) biodegradable polyester Bacillus cereus endophytic bacteria 

摘      要：BACKGROUND： Bacteria endogenously residing within the plant tissues have attracted significant attention for production of biopolyester, polyhydroxyalkanoates （PHAs）. Bacillus cereus RCL 02 （MCC 3436）, a leaf endophyte of oleaginous plant Ricinus communis L. accumulates 81% poly（3-hydroxybutyrate） [P（3HB）] of its cell dry biomass when grown in mineral salts （MS） medium. METHODS： The copolymer production efficiency of B. cereus RCL 02 was evaluated in valeric acid supplemented MS medium under biphasic cultivation condition. The copolymer so produced has been compared with the P（3HB） isolated from RCL 02 in terms of thermal, mechanical and chemical properties. RESULTS： Valeric acid supplementation as co-substrate in the medium has led to the production of copolymer of 3- hydroxybutyrate （3HB） and 3-hydroxyvalerate （3HV） [P（3HB-co-3HV）] with 14.6 mol% 3HV. The identity of the polymers has been confirmed by X-ray diffraction （XRD） analysis, Fourier transform infrared （FTIR） and nuclear magnetic resonance （NMR） spectroscopic studies. Thermogravimetric analysis （TGA） revealed that P（3HB） and P（3HB-co-3HV） films degraded at 278.66℃ and 273.49℃, respectively. The P（3HB-co-3HV） showed lower melting temperature （165.03℃） compared to P （3HB） （170.74℃） according to differential scanning calorimetry （DSC）. Incorporation of 3HV monomers decreased the tensile strength （21.52 MPa）, tensile modulus （0.93 GPa）, storage modulus （E＇） （0.99 GPa） and increased % elongation at break （12.2%） of the copolyester. However, P（3HB） showed better barrier properties with lower water vapor transmission rate （WVTR） of 0.55 g-mil/100 in2/24 h. CONCLUSION： These findings emphasized exploration of endophytic bacterial strain （RCL 02） to produce biodegradable polyesters which might have significant potential for industrial application.