Studies on fermentation‐broth rheology of a penicillium strain with cellulose as substrate

Manchanda, Arushi; Jogdand, V. V.; Karanth, N. G.

doi:10.1002/jctb.5030320608

Cited by 3 publications

(1 citation statement)

References 12 publications

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“…The filamentous fungi Trichoderma reesei and Penicillium funiculosum produce a diversity of glycoside hydrolase enzymes that are considered critical for the saccharification of both the hemicellulose and the cellulosic components of plant cell walls (Chen et al 1987;Elshafei et al 1991;Foreman et al 2003;Gaur and Mishra 1990;Lachke et al 1987;Manchanda et al 1982). These two fungal species of commercial importance produce cellobiohydrolase enzymes in abundant quantities.…”

Section: Introductionmentioning

confidence: 98%

Probing the role of N-linked glycans in the stability and activity of fungal cellobiohydrolases by mutational analysis

et al. 2009

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The filamentous fungi Trichoderma reesei and Penicillium funiculosum produce highly effective enzyme mixtures that degrade the cellulose and hemicellulose components of plant cell walls. Many fungal species produce a glycoside hydrolase family 7 (Cel7A) cellobiohydrolase, a class of enzymes that catalytically process from the reducing end of cellulose. A direct amino acid comparison of these two enzymes shows that they not only have high amino acid homology, but also contain analogous N-linked glycosylation sites on the catalytic domain. We have previously shown (Jeoh et al. in Biotechnol Biofuels, 1:10, 2008) that expression of T. reesei cellobiohydrolase I in a commonly used industrial expression host, Aspergillus niger var.awamori, results in an increase in the amount of Nlinked glycosylation of the enzyme, which negatively affects crystalline cellulose degradation activity as well as thermal stability. This complementary study examines the significance of individual N-linked glycans on the surface of the catalytic domain of Cel7A cellobiohydrolases from T. reesei and P. funiculosum by genetically adding or removing N-linked glycosylation motifs using site directed mutagenesis. Modified enzymes, expressed in A. niger var. awamori, were tested for activity and thermal stability. It was concluded that N-linked glycans in peptide loops that form part of the active site tunnel have the greatest impact on both thermal stability and enzymatic activity on crystalline cellulose for both the T. reesei and P. funiculosum Cel7A enzymes. Specifically, for the Cel7A T. reesei enzyme expressed in A. niger var. awamori, removal of the N384 glycosylation site yields a mutant with 70% greater activity after 120 h compared to the heterologously expressed wild type T. reesei enzyme. In addition, similar activity improvements were found to be associated with the addition of a new glycosylation motif at N194 in P. funiculosum. This mutant also exhibits 70% greater activity after 120 h compared to the wild type P. funiculosum enzyme expressed in A. niger var. awamori. Overall, this study demonstrates that ''tuning'' enzyme glycosylation for expression from heterologous expression hosts is essential for generating engineered enzymes with optimal stability and activity.

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Section: Introductionmentioning

confidence: 98%

Probing the role of N-linked glycans in the stability and activity of fungal cellobiohydrolases by mutational analysis

et al. 2009

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Rheological studies on Streptomyces fradiae ScF‐5 in submerged fermentation

Ghildyal

Thakur

Srikanta

et al. 1987

J of Chemical Tech & Biotech

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Studies on the rheology of Streptomyces fradiae ScF‐5 in a 10‐dm3 submerged fermenter for the production of intracellular glucose isomerase revealed that the apparent viscosity of the broth increased with increase in cell density up to 24 h and then declined while the density of the broth remained constant. The plot of shear stress versus shear rate at various fermentation periods showed the applicability of the Casson model. The yield stress and consistency index were found to increase gradually then decrease subsequently. In contrast, the flow behaviour index was less than unity and remained constant throughout the fermentation. The results contrast with the findings of other workers on the Newtonian and non‐Newtonian character of fermentation broths and the applicability of the power law model to such systems.

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Studies on cellulase production by a Penicillium funiculosum strain in an instrumented fermenter

Joglekar¹,

Srinivasan²,

Manchanda³

et al. 1983

Enzyme and Microbial Technology

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Studies on fermentation‐broth rheology of a penicillium strain with cellulose as substrate

Cited by 3 publications

References 12 publications

Probing the role of N-linked glycans in the stability and activity of fungal cellobiohydrolases by mutational analysis

Probing the role of N-linked glycans in the stability and activity of fungal cellobiohydrolases by mutational analysis

Rheological studies on Streptomyces fradiae ScF‐5 in submerged fermentation

Studies on cellulase production by a Penicillium funiculosum strain in an instrumented fermenter

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