Effects of heterologous expression of phosphoenolpyruvate carboxykinase and phosphoenolpyruvate carboxylase on organic acid production in Aspergillus carbonarius

Abstract Background In filamentous fungi, transport of organic acids across the mitochondrial membrane is facilitated by active transport via shuttle proteins. These transporters may transfer different organic acids across the membrane while taking others the opposite direction. In Aspergillus niger, accumulation of malate in the cytosol can trigger production of citric acid via the exchange of malate and citrate across the mitochondrial membrane. Several mitochondrial organic acid transporters were recently studied in A. niger showing their effects on organic acid production. Results In this work, we studied another citric acid producing fungus, Aspergillus carbonarius, and identified by genome-mining a putative mitochondrial transporter MtpA, which was not previously studied, that might be involved in production of citric acid. This gene named mtpA encoding a putative oxaloacetate transport protein was expressed constitutively in A. carbonarius based on transcription analysis. To study its role in organic acid production, we disrupted the gene and analyzed its effects on production of citric acid and other organic acids, such as malic acid. In total, 6 transformants with gene mtpA disrupted were obtained and they showed secretion of malic acid at the expense of citric acid production. Conclusion A putative oxaloacetate transporter gene which is potentially involved in organic acid production by A. carbonarius was identified and further investigated on its effects on production of citric acid and malic acid. The mtpA knockout strains obtained produced less citric acid and more malic acid than the wild type, in agreement with our original hypothesis. More extensive studies should be conducted in order to further reveal the mechanism of organic acid transport as mediated by the MtpA transporter.

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Deletion of glucose oxidase changes the pattern of organic acid production in Aspergillus carbonarius

AMB Express ◽

10.1186/s13568-014-0054-7 ◽

2014 ◽

Vol 4 (1) ◽

Cited By ~ 24

Author(s):

Lei Yang ◽

Mette Lübeck ◽

Peter S Lübeck

Keyword(s):

Organic Acid ◽

Glucose Oxidase ◽

Acid Production ◽

Aspergillus Carbonarius ◽

Organic Acid Production

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Sites of Organic Acid Production and Patterns of Digesta Movement in the Gastrointestinal Tract of Dogs

Journal of Nutrition ◽

10.1093/jn/109.9.1592 ◽

1979 ◽

Vol 109 (9) ◽

pp. 1592-1600 ◽

Cited By ~ 68

Author(s):

Charles A. Banta ◽

Edgar T. Clemens ◽

Mary M. Krinsky ◽

Ben E. Sheffy

Keyword(s):

Gastrointestinal Tract ◽

Organic Acid ◽

Acid Production ◽

Organic Acid Production

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Microbial Applications in Organic Acid Production

10.1002/9781119717317.ch6 ◽

2021 ◽

pp. 104-124

Author(s):

Jyoti Singh Jadaun ◽

Amit K. Rai ◽

Sudhir P. Singh

Keyword(s):

Organic Acid ◽

Acid Production ◽

Organic Acid Production

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Genes involved in lactose catabolism and organic acid production during growth of Lactobacillus delbrueckii UFV H2b20 in skimmed milk

Beneficial Microbes ◽

10.3920/bm2011.0037 ◽

2012 ◽

Vol 3 (1) ◽

pp. 23-32 ◽

Cited By ~ 4

Author(s):

A. Do Carmo ◽

M. De Oliveira ◽

D. Da Silva ◽

S. Castro ◽

A. Borges ◽

...

Keyword(s):

Lactic Acid ◽

Organic Acid ◽

Acid Production ◽

Food Preservation ◽

Starter Cultures ◽

Lactobacillus Delbrueckii ◽

Probiotic Properties ◽

Organic Acid Production ◽

Probiotic Lactobacillus ◽

Skimmed Milk

There are three main reasons for using lactic acid bacteria (LAB) as starter cultures in industrial food fermentation processes: food preservation due to lactic acid production; flavour formation due to a range of organic molecules derived from sugar, lipid and protein catabolism; and probiotic properties attributed to some strains of LAB, mainly of lactobacilli. The aim of this study was to identify some genes involved in lactose metabolism of the probiotic Lactobacillus delbrueckii UFV H2b20, and analyse its organic acid production during growth in skimmed milk. The following genes were identified, encoding the respective enzymes: ldh – lactate dehydrogenase, adhE – Ldb1707 acetaldehyde dehydrogenase, and ccpA-pepR1 – catabolite control protein A. It was observed that L. delbrueckii UFV H2b20 cultivated in different media has the unexpected ability to catabolyse galactose, and to produce high amounts of succinic acid, which was absent in the beginning, raising doubts about the subspecies in question. The phylogenetic analyses showed that this strain can be compared physiologically to L. delbrueckii subsp. bulgaricus and L. delbrueckii subsp. lactis, which are able to degrade lactose and can grow in milk. L. delbrueckii UFV H2b20 sequences have grouped with L. delbrueckii subsp. bulgaricus ATCC 11842 and L. delbrueckii subsp. bulgaricus ATCC BAA-365, strengthening the classification of this probiotic strain in the NCFM group proposed by a previous study. Additionally, L. delbrueckii UFV H2b20 presented an evolutionary pattern closer to that of probiotic Lactobacillus acidophilus NCFM, corroborating the suggestion that this strain might be considered as a new and unusual subspecies among L. delbrueckii subspecies, the first one identified as a probiotic. In addition, its unusual ability to metabolise galactose, which was significantly consumed in the fermentation medium, might be exploited to produce low-browning probiotic Mozzarella cheeses, a desirable property for pizza cheeses.

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Part III. The Respiratory Regulation in Psychotic Subjects

Journal of Mental Science ◽

10.1192/bjp.74.306.443 ◽

1928 ◽

Vol 74 (306) ◽

pp. 443-453 ◽

Cited By ~ 18

Author(s):

F. Golla ◽

S. A. Mann ◽

F. Golla ◽

R. G. B. Marsh

Keyword(s):

Organic Acid ◽

Acid Production ◽

Normal Subjects ◽

Compensatory Mechanism ◽

Acid Base ◽

Organic Acid Production ◽

Respiratory Regulation ◽

Acid Base Equilibrium ◽

Buffering Power ◽

Respiratory Centre

The preceding studies on the acid-base equilibrium in psychotics have made it evident that the failure to adjust must be attributed in the first instance to an inadequacy of the respiratory compensatory mechanism, and can be in no sense attributable to either a deficiency in the buffering power of the blood itself or to an increased organic acid production (acidosis). We have endeavoured to determine the excitability of the respiratory centre to the stimulus created by CO2. For this purpose a number of psychotic patients were tested as to the excitability of the respiratory centre to air containing 2% CO2 and the reaction compared with that obtaining in a number of normal subjects.

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