Metabolism Induces Formation of Calcium Carbonate

Biological Strategy

Alternaria

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Chemically Assemble Mineral Crystals

The vast majority of biochemical assembly and break down processes––even by the most complex organisms––occur within cells. In fact, cells are able to perform hundreds, even thousands, of chemical transformations at the same time under life-friendly conditions (ambient temperature and pressure in an aqueous environment). Within cells, organisms utilize organic compounds to facilitate the assembly of mineral crystals. For example, oysters utilize acidic proteins and sulfated polysaccharides to assemble layers of aragonite crystals.

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Chemically Assemble on Demand

The vast majority of biochemical assembly and break down processes––even by the most complex organisms––occur within cells. In fact, cells are able to perform hundreds, even thousands, of chemical transformations at the same time under life-friendly conditions (ambient temperature and pressure in an aqueous environment). For example, venomous snakes store precursor molecules to instantly synthesize a suite of toxins via enzyme-mediated cascades.

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Fungi

Kingdom Fungi: Mildews, molds, mushrooms, rusts, smuts, and yeasts

Once thought to be more closely related to plants, fungi have been found to contain chitin in their cell walls, indicating a closer evolutionary relationship to animals. Fungi are decomposers, using digestive enzymes to break down their surroundings, making them an essential part of ecosystems worldwide, as new soil is formed from rotting matter. Almost all fungi reproduce through spores (mushrooms, molds) or asexual budding (some yeast). There are estimated to be more than 2 million species, but only about 140,000 have been described. Fungi have great importance in culture, food, and medicine (including being the source of penicillin) worldwide.

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Metabolism in Alternaria fungi sequestrate carbon dioxide by forming calcium carbonate through the assimilation of nitrate.

Fungi are the dominant microbes in soil. They are an essential part of many ecosystems because they help recycle nutrients from the atmosphere and ground alike (fungi are often associated with decomposition). Fungi from the genus Alternaria take up nitrate from moist soils and convert it to ammonium ion, increasing the pH of the soil in the process. As a result, the carbon dioxide “exhaled” from their respiration gets converted to solid calcium carbonate in the soil before it has a chance to escape into the air as carbon dioxide gas.

Last Updated August 23, 2016

References

Journal article

CO2 mineralization induced by fungal nitrate assimilation

Bioresource Technology | 27/08/2010 | Weiguo Hou, Bin Lian, Xiaoqing Zhang

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