Partial characterization of amylases of two indigenous central amazonian rhizobia strains

• Autor(a) principal: Oliveira, Arlem Nascimento de
• Data de Publicação: 2010
• Outros Autores: Oliveira, Luiz Antonio de, Andrade, Jerusa Souza
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional do INPA
• Texto Completo: https://repositorio.inpa.gov.br/handle/1/16270
• topic: Bradyrhizobium; Rhizobiaceae; Rhizobium

Amylase production and partial characterization of crude enzyme preparations from two rhizobia strains (R-926 and R-991) were evaluated. For both the strains, maximal amylase activities were achieved during the early-to-midexponential growth phase; both were active over a pH range from 4.5 to 8.5 and temperature from 30 to 50 °C. None of the ions studied (K+, Na+, Ca2+, Hg2+, Mg2+, Mn2+, Cu2+ and Zn2+) was required for the catalytic activity of strain R-926; amylase activity of strain R-991 was stimulated in the presence of K+, Hg2+ and Zn2+. The surfactants SDS, Triton X-100 and Tween-80 did not have a pronounced inhibitory effect on enzyme activities; SDS and Tween-80 caused the highest stimulatory effects. Amylase activities from the rhizobia strains were reduced by up to 30% in the presence of EDTA; amylase activity of R-926 was also inhibited by HgCl2, suggesting that Ca2+and cysteine residues could be important for activity of this strain.