Dataset Information

Improved biomass and protein production in solid-state cultures of an Aspergillus sojae strain harboring the Vitreoscilla hemoglobin.

ABSTRACT: The biotechnological value of Aspergillus sojae ATCC 20235 (A. sojae) for production of pectinases in solid-state fermentation (SSF) has been demonstrated recently. However, a common drawback of fungal solid-state cultures is the poor diffusion of oxygen into the fungi that limits its growth and biological productivity. The bacterial Vitreoscilla hemoglobin (VHb) has favored the metabolism and productivities of various bacterial and yeast strains besides alleviating hypoxic conditions of its native host, but the use of VHb in filamentous fungi still remains poor explored. Based on the known effects of VHb, this study assessed its applicability to improve A. sojae performance in SSF. The VHb gene (vgb) under control of the constitutive Aspergillus nidulants gpdA promoter was introduced into the genome of A. sojae by Agrobacterium-mediated transformation. Successful fungal transformants were identified by fluorescence microscopy and polymerase chain reaction (PCR) analyses. In solid-state cultures, the content of protease, exo-polygalacturonase (exo-PG), and exo-polymethylgalacturonase (exo-PMG) of the transformed fungus (A. sojae vgb+) improved were 26, 60, and 44 % higher, respectively, in comparison to its parental strain (A. sojae wt). Similarly, biomass content was also 1.3 times higher in the transformant strain. No significant difference was observed in endo-polygalacturonase (endo-PG) content between both fungal strains, suggesting dissimilar effects of VHb towards different enzymatic productions. Overall, our results show that biomass, protease, and exo-pectinase content of A. sojae in SSF can be improved by transformation with VHb.

SUBMITTER: Mora-Lugo R

PROVIDER: S-EPMC4628083 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature

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Improved biomass and protein production in solid-state cultures of an Aspergillus sojae strain harboring the Vitreoscilla hemoglobin.

Mora-Lugo Rodrigo R Madrigal Marvin M Yelemane Vikas V Fernandez-Lahore Marcelo M

Applied microbiology and biotechnology 20150730 22

The biotechnological value of Aspergillus sojae ATCC 20235 (A. sojae) for production of pectinases in solid-state fermentation (SSF) has been demonstrated recently. However, a common drawback of fungal solid-state cultures is the poor diffusion of oxygen into the fungi that limits its growth and biological productivity. The bacterial Vitreoscilla hemoglobin (VHb) has favored the metabolism and productivities of various bacterial and yeast strains besides alleviating hypoxic conditions of its nat ...[more]

PMID: 26224427

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Project description:Hypoxia, a naturally occurring phenomenon, results in tremendous losses in the growth of plants and in their productivity. On the physiological level oxygen deprivation results in distinct metabolic rearrangements, is accompanied by dehydration, and oxidative and nitrosative stresses. Six to seven core hypoxia-responsive genes, which are always induced under oxygen deprivation, have been shown to include hemoglobin 1 (Hb1) across a wide range of plant species. However, the function of this induced Hb1 is not completely understood .The importance of elevated Hb expression has been attributed mainly to its nitric oxide (NO) scavenging properties, and hence, to the elimination of this free-radical and signaling species. NO is known to accumulate under hypoxia and its level is in reciprocal relationship with the Hb expression levels. However, evidence has accumulated on Hbs as essential for normal plant development and they take part in the regulation of e.g. flowering, germination and lateral and adventitious root emergence. The physiological role of induced hemoglobin (Hb) expression and its role in NO scavenging were assessed by introducing bacterial (Vitreoscilla stercoraria) hemoglobin (VHb) to the cytoplasm and mitochondria of Arabidopsis thaliana. Heterologous expression was chosen to avoid interference with developmental functions of endogenous Hbs. Sixteen day old transformants were subjected to hypoxia or to NO donor treatment (DETA, 500 µM) for 2h and 24h and global changes in gene expression were assessed using a microarray approach. Both hypoxic and NO-treatment experiments were aimed also to reveal novel functions for Hb under abiotic stress conditions, exemplified by oxygen deprivation and NO/oxidative stresses and during normal development of Arabidopsis transformants on the background of normally expressed endogenous Hbs Hypoxia, a naturally occurring phenomenon, results in tremendous losses in the growth of plants and in their productivity. On the physiological level oxygen deprivation results in distinct metabolic rearrangements, is accompanied by dehydration, and oxidative and nitrosative stresses. Six to seven core hypoxia-responsive genes, which are always induced under oxygen deprivation, have been shown to include hemoglobin 1 (Hb1) across a wide range of plant species. However, the function of this induced Hb1 is not completely understood .The importance of elevated Hb expression has been attributed mainly to its nitric oxide (NO) scavenging properties, and hence, to the elimination of this free-radical and signaling species. NO is known to accumulate under hypoxia and its level is in reciprocal relationship with the Hb expression levels. However, evidence has accumulated on Hbs as essential for normal plant development and they take part in the regulation of e.g. flowering, germination and lateral and adventitious root emergence. The physiological role of induced hemoglobin (Hb) expression and its role in NO scavenging were assessed by introducing bacterial (Vitreoscilla stercoraria) hemoglobin (VHb) to the cytoplasm and mitochondria of Arabidopsis thaliana. Heterologous expression was chosen to avoid interference with developmental functions of endogenous Hbs. Sixteen day old transformants were subjected to hypoxia or to NO donor treatment (DETA, 500 µM) for 2h and 24h and global changes in gene expression were assessed using a microarray approach. Both hypoxic and NO-treatment experiments were aimed also to reveal novel functions for Hb under abiotic stress conditions, exemplified by oxygen deprivation and NO/oxidative stresses and during normal development of Arabidopsis transformants on the background of normally expressed endogenous Hbs

Dataset Information

Improved biomass and protein production in solid-state cultures of an Aspergillus sojae strain harboring the Vitreoscilla hemoglobin.

Publications

Improved biomass and protein production in solid-state cultures of an Aspergillus sojae strain harboring the Vitreoscilla hemoglobin.

Similar Datasets

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