Fungal morphology and metabolite production in submerged mycelial processes.

Advances in citric acid fermentation by Aspergillus niger: biochemical aspects, membrane transport and modeling.

Citric Acid Fermentation

Organic acid concentrations often increase with iron deficiency in different plant parts such as roots, leaves and stem exudates. The review summarises data available on the changes in the concentrations of organic anions in plants with iron deficiency and the effects of these changes in plant metabolism. The paper reviews data available in the literature on the changes in xylem and apoplasmic fluid composition with iron deficiency, both in plants grown in controlled conditions and in the field, and discusses the possible ways of iron complexation and transport in these compartments. The characteristics of the iron reduction and uptake by the iron-deficient leaf mesophyll cells are also discussed, with especial emphasis in the possible roles of organic acids in these processes. Both the possible causes and functions of the organic acid concentration increases in iron-deficient plants are reviewed.

Organic acids and Fe deficiency : a review

Citric acid is a commodity chemical produced and consumed throughout The World. It is used mainly in the food and beverage industry, primarily as an acidulant. Although it is one of the oldest industrial fermentations, its World production is still in rapid increasing. Global production of citric acid in 2007 was over 1.6 million tones. Biochemistry of citric acid fermentation, various microbial strains, as well as various substrates, technological processes and product recovery are presented. World production and economics aspects of this strategically product of bulk biotechnology are discussed.

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C.P. Kubicek

Papers

Phosphofructokinase as a regulatory enzyme in citric acid producing Aspergillus niger