Thermal and Rheological Properties of a Family of Botryosphaerans Produced by Botryosphaeria rhodina MAMB-05

Made available in DSpace on 2013-08-28T14:07:22Z (GMT). No. of bitstreams: 1 WOS000295211000023.pdf: 422179 bytes, checksum: 9e96ed2bf3237d547956e48f80dcd461 (MD5) Made available in DSpace on 2013-09-30T18:09:29Z (GMT). No. of bitstreams: 2 WOS000295211000023.pdf: 422179 bytes, checksum: 9e96ed2bf3237d547956e48f80dcd461 (MD5) WOS000295211000023.pdf.txt: 37101 bytes, checksum: 468b5bec7bde38bd684ddc8137cdd0a4 (MD5) Previous issue date: 2011-09-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:23:09Z No. of bitstreams: 2 WOS000295211000023.pdf: 422179 bytes, checksum: 9e96ed2bf3237d547956e48f80dcd461 (MD5) WOS000295211000023.pdf.txt: 37101 bytes, checksum: 468b5bec7bde38bd684ddc8137cdd0a4 (MD5) Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:23:09Z No. of bitstreams: 2 WOS000295211000023.pdf: 422179 bytes, checksum: 9e96ed2bf3237d547956e48f80dcd461 (MD5) WOS000295211000023.pdf.txt: 37101 bytes, checksum: 468b5bec7bde38bd684ddc8137cdd0a4 (MD5) Made available in DSpace on 2014-05-20T13:23:09Z (GMT). No. of bitstreams: 2 WOS000295211000023.pdf: 422179 bytes, checksum: 9e96ed2bf3237d547956e48f80dcd461 (MD5) WOS000295211000023.pdf.txt: 37101 bytes, checksum: 468b5bec7bde38bd684ddc8137cdd0a4 (MD5) Previous issue date: 2011-09-01 Made available in DSpace on 2014-05-20T13:23:09Z (GMT). No. of bitstreams: 2 WOS000295211000023.pdf: 422179 bytes, checksum: 9e96ed2bf3237d547956e48f80dcd461 (MD5) WOS000295211000023.pdf.txt: 37101 bytes, checksum: 468b5bec7bde38bd684ddc8137cdd0a4 (MD5) Previous issue date: 2011-09-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) PROPPG-UEL Differential scanning calorimetry (DSC), thermogravimetry (TG) and Fourier-transform infra-red spectroscopy (FT-IR) analyses were performed to investigate changes in the physico-chemical properties of botryosphaerans, a family of exopolysaccharides (EPS) produced by the fungus Botryosphaeria rhodina MAMB-05 grown on glucose (EPS(GLC)), sucrose (EPS(SUC)) and fructose (EPS(FRU)). A slight endothermic transition and small mass loss attributable to the removal of water of hydration were observed in the DSC and TG analyses, respectively, for the three EPS samples. The FT-IR spectra confirmed no structural changes occurred during thermal treatment. Viscometry was utilized to obtain information on the rheological behaviour of the EPS in aqueous solutions. The Power Law and Cross Equations determined the natural pseudoplastic characteristics of the EPS. Comparatively, results obtained for EPS produced when B. rhodina MAMB-05 was grown on each of the three carbohydrate sources demonstrated similar apparent viscosity values for EPS(GLC) and EPS(SUC), while EPS(FRU) displayed the lowest apparent viscosity of the three botryosphaerans, suggesting a higher degree of ramification and lower Mw. EPS(GLC) and EPSSUC possessed similar degrees of ramification. The slight differences found in their viscosities can be explained by the differences in the type of branching among the three botryosphaerans, thus varying the strength of intermolecular interactions and consequently, consistency and viscosity. The physico-chemical studies of botryosphaerans represent the originality of this work, and the knowledge of these properties is an important criterion for potential applications. Univ Estadual Paulista, Fac Sci & Technol, Dept Phys Chem & Biol, BR-19060900 Presidente Prudente, Brazil Lakehead Univ, Biorefining Res Initiat, Thunder Bay, on P7B 5E1, Canada Univiversidade Estadual de Londrina (UEL), Dept Biochem & Biotechnol, CCE, BR-86051990 Londrina, Brazil Univ Fed Parana, Dept Biochem & Mol Biol, BR-81531990 Curitiba, Parana, Brazil Univ Estadual Paulista, Fac Sci & Technol, Dept Phys Chem & Biol, BR-19060900 Presidente Prudente, Brazil