Volume 4 Issue 1

Volume 4 Issue 1

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Research Article 

Production and Functional Properties of Free and Immobilized Glucoamylases of Penicillium citrinum

Caio Cesar de Carvalho, Luciana Sobrani Ziotti, Marita Gimenez Pereira, Andrezza Furquim da Cruz, João Atílio Jorge, Maria de Lourdes Teixeira Moraes Polizeli*

Amylases are enzymes with important biotechnological applications that are produced by several microorganisms in the form of filamentous fungi. Penicillium citrinum was recently isolated from the decomposed materials of tlantic Forest, Brazil. It was identified by internal transcribed spacer (ITS) and beta-tubulin, and presented with excellent amylolytic levels. Thin layer chromatography showed that the amylase system was constituted by glucoamylase. This enzyme showed high activity at 60°C, pH 5.5, and an increment of 160% of the relative activity in the presence of 2 mM MgCl2.

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Research Article 

Assessment of the Role of Extracellular DNA and Protozoan Grazing in Aerobic Granular Sludge Development

Sodhi N, Scott A Rice, Staffan Kjelleberg, Diane McDougald*

A scaled-down batch reactor system, modelled on traditional laboratory scale batch reactors, was developed for the preliminary assessment of the role of a number of factors on microbial aggregation. Long-term batch reactors were used to investigate the role of extracellular DNA in the re-granulation of crushed granular sludge, while short-term reactors were used to assess the impact of protozoan grazing on aggregation and microbial community structure. Extracellular DNA was observed as halos and honeycomb structures within granules and was found to be integral to granular architecture. Grazing by heterotrophic protists was shown to increase and maintain aggregate size as well as significantly affect the microbial community structure.

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