Fungal Production of Citric and Oxalic Acid: Importance in Metal Speciation, Physiology and Biogeochemical Processes

Gadd, Geoffrey M.

doi:10.1016/s0065-2911(08)60165-4

Cited by 591 publications

(471 citation statements)

References 202 publications

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“…1). This cycle demonstrates that calcium oxalate produced by both plants (Horner and Wagner 1995) and fungi (Cromack et al 1977;Gadd 1999) can be transformed into CaCO 3 by bacteria (Braissant et al 2002). The pH increase induced by this cycle is favourable to CaCO 3 precipitation and accumulation, as carbonic acid is weaker (pK 1 =6.35; pK 2 =10.33) than oxalic acid (pK 1 =1.25; pK 2 =4.27).…”

Section: Resultsmentioning

confidence: 94%

Biomineralization in plants as a long-term carbon sink

Cailleau

Braissant

Verrecchia

2004

Naturwissenschaften

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Carbon sequestration in the global carbon cycle is almost always attributed to organic carbon storage alone, while soil mineral carbon is generally neglected. However, due to the longer residence time of mineral carbon in soils (10 2 -10 6 years), if stored in large quantities it represents a potentially more efficient sink. The aim of this study is to estimate the mineral carbon accumulation due to the tropical iroko tree (Milicia excelsa) in Ivory Coast. The iroko tree has the ability to accumulate mineral carbon as calcium carbonate (CaCO 3 ) in ferralitic soils, where CaCO 3 is not expected to precipitate. An estimate of this accumulation was made by titrating carbonate from two characteristic soil profiles in the iroko environment and by identifying calcium (Ca) sources. The system is considered as a net carbon sink because carbonate accumulation involves only atmospheric CO 2 and Ca from Ca-carbonate-free sources. Around one ton of mineral carbon was found in and around an 80-year-old iroko stump, proving the existence of a mineral carbon sink related to the iroko ecosystem. Conservation of iroko trees and the many other biomineralizing plant species is crucial to the maintenance of this mineral carbon sink.

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Section: Resultsmentioning

confidence: 94%

Biomineralization in plants as a long-term carbon sink

Cailleau

Braissant

Verrecchia

2004

Naturwissenschaften

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“…Oxalic acid is generated during tobacco fermentation (Table 2) and represents an undesirable end product. In yeasts and filamentous fungi, biosynthesis of oxalic acid occurs as a byproduct of malic and citric acid metabolism via hydrolysis of oxaloacetic acid and glyoxylate oxidation, respectively (16,44). Oxalic acid production in TB medium was maximal with C. rugosa and D. hansenii, which preferentially catabolized malic acid, while it was barely detectable with C. parapsilosis, which preferentially utilized citric acid (see Fig.…”

Section: Discussionmentioning

confidence: 99%

Microbial Community Structure and Dynamics of Dark Fire-Cured Tobacco Fermentation

Giacomo¹,

Paolino²,

Silvestro³

et al. 2007

Appl Environ Microbiol

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The Italian Toscano cigar production includes a fermentation step that starts when dark fire-cured tobacco leaves are moistened and mixed with ca. 20% prefermented tobacco to form a 500-kg bulk. The dynamics of the process, lasting ca. 18 days, has never been investigated in detail, and limited information is available on microbiota involved. Here we show that Toscano fermentation is invariably associated with the following: (i) an increase in temperature, pH, and total microbial population; (ii) a decrease in reducing sugars, citric and malic acids, and nitrate content; and (iii) an increase in oxalic acid, nitrite, and tobacco-specific nitrosamine content. The microbial community structure and dynamics were investigated by culture-based and cultureindependent approaches, including denaturing gradient gel electrophoresis and single-strand conformational polymorphism. Results demonstrate that fermentation is assisted by a complex microbial community, changing in structure and composition during the process. During the early phase, the moderately acidic and mesophilic environment supports the rapid growth of a yeast population predominated by Debaryomyces hansenii. At this stage, Staphylococcaceae (Jeotgalicoccus and Staphylococcus) and Lactobacillales (Aerococcus, Lactobacillus, and Weissella) are the most commonly detected bacteria. When temperature and pH increase, endospore-forming low-G؉C content gram-positive bacilli (Bacillus spp.) become evident. This leads to a further pH increase and promotes growth of moderately halotolerant and alkaliphilic Actinomycetales (Corynebacterium and Yania) during the late phase. To postulate a functional role for individual microbial species assisting the fermentation process, a preliminary physiological and biochemical characterization of representative isolates was performed.

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“…Different kinds of interactions exist between microorganisms and minerals in our environment (Ehrlich 1997;Gadd 1999). These interactions have been extensively studied in the mining industries to produce technologies that are beneficial such as mineralisation, bioremediation and biohydrometallurgy (Ehrlich 1997;Gadd 1999;Rawlings 2002).…”

Section: Introductionmentioning

confidence: 99%

Mobilisation of potassium and phosphorus from iron ore by ectomycorrhizal fungi

Adeleke

Cloete

Bertrand

et al. 2010

World J Microbiol Biotechnol

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Mutualistic roles of ectomycorrhizal (ECM) fungi have been linked to their ability to produce organic acids that aid in the dissolution of insoluble minerals in the rhizosphere. This ability of ECM fungi was utilised to investigate their potential participation in the mobilisation of nutrients such as phosphorus (P) and potassium (K) from a typical insoluble ore-iron ore. In vitro pure cultures of four different ECM fungi; Pisolithus tinctorius, Paxillus involutus, Phialocephala fortini, and Suillus tomentosus were screened for their ability to mobilise P and K from two types of non-exportable Sishen iron ore. When present in iron ore, these elements are deleterious and reduce the commercial values of the ore. Experiment was set up with different treatments that included two ore types (KGT and SK) and five particle sizes of each ore type. Results indicated the potential of the four fungi to mobilise P and K from the two iron ore types though at different levels. Ore type, particle size, organic acid production and attachment of the fungi to the iron ore were all found to play important roles in the mobilisation of nutrients from these ores.

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Fungal Production of Citric and Oxalic Acid: Importance in Metal Speciation, Physiology and Biogeochemical Processes

Cited by 591 publications

References 202 publications

Biomineralization in plants as a long-term carbon sink

Biomineralization in plants as a long-term carbon sink

Microbial Community Structure and Dynamics of Dark Fire-Cured Tobacco Fermentation

Mobilisation of potassium and phosphorus from iron ore by ectomycorrhizal fungi

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