Xylanases from Aspergillus niger, Aspergillus niveus and Aspergillus ochraceus produced under solid-state fermentation and their application in cellulose pulp bleaching

Bioprocess Biosyst Eng (2009) 32:819–824

J. H. A. Betini, M. Michelin, S. C. Peixoto-Nogueira, J. A. Jorge, H. F. Terenzi, M. L. T. M. Polizeli

This study describes the production of xylanases from Aspergillus niveus, A. niger, and A. ochraceus under solid-state fermentation using agro-industrial residues as substrates. Enzyme production was improved using a mixture of wheat bran and yeast extract or peptone. When a mixture of corncob and wheat bran was used, xylanase production from A. niger and A. ochraceus increased by 18%. All cultures were incubated at 30ºC at 70–80% relative humidity for 96 h. For biobleaching assays, 10 or 35 U of xylanase/g dry cellulose pulp were incubated at pH 5.5 for 1 or 2 h, at 55ºC. The delignification efficiency was 20%, the brightness (percentage of ISO) increased two to three points and the viscosity was maintained confirming the absence of cellulolytic activity. These results indicated that the use of xylanases could help to reduce the amount of chlorine compounds used in cellulose pulp treatment.

Evidence of thermostable amylolytic activity from Rhizopus microsporus var. rhizopodiformis using wheat bran and corncob as alternative carbon source

Bioprocess Biosyst Eng (2008) 31:329–334

S. C. Peixoto-Nogueira, V. C. Sandrim, L. H. S. Guimarães, J. A. Jorge, H. F. Terenzi, M. L. T. M. Polizeli

DOI 10.1007/s00449-007-0166-4

Rhizopus microsporus var. rhizopodiformis produced high levels of a-amylase and glucoamylase under solid state fermentation, with several agricultural residues, such as wheat bran, cassava flour, sugar cane bagasse, rice straw, corncob and crushed corncob as carbon sources. These materials were humidified with distilled water, tap water, or saline solutions—Segato Rizzatti (SR), Khanna or Vogel. The best substrate for amylase production was wheat bran with SR saline solution (1:2 v/v). Amylolytic activity was still improved (14.3%) with a mixture of wheat bran, corncob, starch and SR saline solution (1:1:0.3:4.6 w/w/w/v). The optimized

Pasteur: Microbiologia e Biotecnologia

Os primeiros estudos acerca da aplicação industrial dos microrganismos foram realizados por Louis Pasteur. Ele descobriu que o vinho era resultante da atividade microbiana e, percebeu também, que diferenças quanto à qualidade deste produto estavam relacionadas ao tipo de microrganismo realizador da fermentação (Pelczar et al., 1997a). Nesta época nada se sabia sobre enzimas e sua produção controlada até que mais tarde a Europa começou a produzir a-amilases e glucoamilases utilizadas na fabricação de açúcares (Crabb & Mitchinson, 1997; Crabb & Shetty, 1999; Kirk et al., 2002) e álcool (Lee, 1997). Posteriormente os conhecimentos foram ampliados para outras enzimas não amilolíticas (http://www.biotecnologia.com.br, Peixoto, S.C. - Dissertação de mestrado).

Foto extraída de: http://www.blogobrando.com/blog/wp-content/uploads/2009/05/louis-pasteur-2.jpg

Leia mais sobre Louis Pasteur em: http://pt.wikipedia.org/wiki/Louis_Pasteur

PEIXOTO, S.C. Estudos comparativos entre as amilases produzidas em cultivo submerso e em substrato sólido pelo fungo termotolerante Rhizopus microsporus var. rhizopodiformis: Purificação e caracterização enzimática. Dissertação apresentada à FFCLRP, para a obtenção do título de Mestre em Ciências, área de concentração: Biologia comparada, pp, 137, 2004.

Replicação do DNA

Veja vídeo ilustrativo do processo de replicação do DNA em: http://www.youtube.com/watch?v=qF-BGYz7wNc


O processo de replicação do material genético ocorre durante o  período S da intérfase que é dividida em G1, S e G2.

Imagem obtida em: http://www.portalsaofrancisco.com.br/alfa/ciclo-celular/imagens/ciclo-celular2.jpg

Quando uma célula não está se "preparando" para a divisão celular é dito que a mesma encontra-se em G0.

Leia mais sobre a intérfase em: http://pt.wikipedia.org/wiki/Int%C3%A9rfase

Production of xylanase by Aspergilli using alternative carbon sources: application of the crude extract on cellulose pulp biobleaching

J Ind Microbiol Biotechnol (2009) 36:149–155

DOI 10.1007/s10295-008-0482-y

Simone de Carvalho Peixoto-Nogueira · Michele Michelin · Jorge Henrique Almeida Betini · João Atílio Jorge · Héctor Francisco Terenzi · Maria de Lourdes Teixeira de Moraes Polizeli

The ability of xylanolytic enzymes produced by Aspergillus fumigatus RP04 and Aspergillus niveus RP05 to promote the biobleaching of cellulose pulp was investigated. Both fungi grew for 4–5 days in liquid medium at

40°C, under static conditions. Xylanase production was tested using diVerent carbon sources, including some types of xylans. A. fumigatus produced high levels of xylanase on agricultural residues (corncob or wheat bran), whereas A. niveus produced more xylanase on birchwood xylan. The optimum temperature of the

"Dinâmica" dos genes

Vídeo interessante! Click no linka abaixo e entenda mais sobre o DNA.

http://www.youtube.com/watch?v=rfuHAxA9Gpc

Autoria de terceiros.

Regulation of xylanase in Aspergillus phoenicis: a physiological and molecular approach

J Ind Microbiol Biotechnol (2008) 35:237–244

Ana Carolina Segato Rizzatti · Fernanda Zanolli Freitas · Maria Célia Bertolini · Simone Carvalho Peixoto-Nogueira · Héctor Francisco Terenzi · João Atílio Jorge · Maria de Lourdes Teixeira de Moraes Polizeli

Microbial xylanolytic enzymes have a promising biotechnological potential, and are extensively applied in industries. In this study, induction of xylanolytic activity was examined in Aspergillus phoenicis. Xylanase activity induced by xylan, xylose or beta-methylxyloside was predominantly extracellular (93–97%). Addition of 1% glucose to media supplemented with xylan or xylose repressed xylanase production. Glucose