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Deletion of the Aspergillus niger Pro-Protein Processing Protease Gene kexB Results in a pH-Dependent Morphological Transition during Submerged Cultivations and Increases Cell Wall Chitin Content.

Author(s): van Leeuwe TM, Arentshorst M, Forn-Cuní G, Geoffrion N, Tsang A, Delvigne F, Meijer AH, Ram AFJ, Punt PJ...

There is a growing interest in the use of post-fermentation mycelial waste to obtain cell wall chitin as an added-value product. In the pursuit to identify suitable production strains that can be u...

Article GUID: 33276589
Antibiotic Pollution in the Environment: From Microbial Ecology to Public Policy.

Author(s): Kraemer SA, Ramachandran A, Perron GG

Microorganisms. 2019 Jun 22;7(6): Authors: Kraemer SA, Ramachandran A, Perron GG

Article GUID: 31234491
Title:Deletion of the Aspergillus niger Pro-Protein Processing Protease Gene kexB Results in a pH-Dependent Morphological Transition during Submerged Cultivations and Increases Cell Wall Chitin Content.
Authors:van Leeuwe TM,  Arentshorst M,  Forn-Cuní G,  Geoffrion N,  Tsang A,  Delvigne F,  Meijer AH,  Ram AFJ,  Punt PJ
Link:https://www.ncbi.nlm.nih.gov/pubmed/33276589
DOI:10.3390/microorganisms8121918
Category:Microorganisms
PMID:33276589
Dept Affiliation: GENOMICS
1 Institute of Biology Leiden, Microbial Sciences, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands.
2 Institute of Biology Leiden, Animal Sciences, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands.
3 Centre for Structural and Functional Genomics, Concordia University, Montreal, QC H4B1R6, Canada.
4 TERRA Teaching and Research Centre, Gembloux Agro-Bio Tech, University of Liège, Avenue de la Faculté, 2B, 5030 Gembloux, Belgium.
5 Dutch DNA Biotech, Hugo R Kruytgebouw 4-Noord, Padualaan 8, 3584 CH Utrecht, The Netherlands.

Description:

Deletion of the Aspergillus niger Pro-Protein Processing Protease Gene kexB Results in a pH-Dependent Morphological Transition during Submerged Cultivations and Increases Cell Wall Chitin Content.

Microorganisms. 2020 Dec 02; 8(12):

Authors: van Leeuwe TM, Arentshorst M, Forn-Cuní G, Geoffrion N, Tsang A, Delvigne F, Meijer AH, Ram AFJ, Punt PJ

Abstract

There is a growing interest in the use of post-fermentation mycelial waste to obtain cell wall chitin as an added-value product. In the pursuit to identify suitable production strains that can be used for post-fermentation cell wall harvesting, we turned to an Aspergillus niger strain in which the kexB gene was deleted. Previous work has shown that the deletion of kexB causes hyper-branching and thicker cell walls, traits that may be beneficial for the reduction in fermentation viscosity and lysis. Hyper-branching of ?kexB was previously found to be pH-dependent on solid medium at pH 6.0, but was absent at pH 5.0. This phenotype was reported to be less pronounced during submerged growth. Here, we show a series of controlled batch cultivations at a pH range of 5, 5.5, and 6 to examine the pellet phenotype of ?kexB in liquid medium. Morphological analysis showed that ?kexB formed wild type-like pellets at pH 5.0, whereas the hyper-branching ?kexB phenotype was found at pH 6.0. The transition of phenotypic plasticity was found in cultivations at pH 5.5, seen as an intermediate phenotype. Analyzing the cell walls of ?kexB from these controlled pH-conditions showed an increase in chitin content compared to the wild type across all three pH values. Surprisingly, the increase in chitin content was found to be irrespective of the hyper-branching morphology. Evidence for alterations in cell wall make-up are corroborated by transcriptional analysis that showed a significant cell wall stress response in addition to the upregulation of genes encoding other unrelated cell wall biosynthetic genes.

PMID: 33276589 [PubMed - as supplied by publisher]