Biomass and organic acids in sandstone of a weathering building: Production by bacterial and fungal isolates

Abstract

Ten fungal and nine bacterial strains were isolated from a weathering sandstone building. Their growth, organic acid production, and acidification capacity were assessed in culture under nutritional conditions similar to those in situ. Biomass (10-50 nmol phospholipid-PO4g(-1)) within the rock was small compared to soils. The isolated organisms were able to produce high amounts of those acids found in the sandstone, but acid production did not cause a drastic reduction in culture pH. It is suggested that the importance of acidification in microbial degradation of sandstone has been overestimated and that, under in situ pH and nutritional conditions, cation chelation by microbially produced organic acid anions may be more relevant to the weathering process.

Nutrient Cycling: Potassium Solubilization by Microorganisms and Improvement of Crop Growth

“…Production of carboxylic acids like citric, tartaric, and oxalic acids was associated with feldspar solubilization by B. mucilaginosus and B. edaphicus (Malinovskaya et al 1990;Sheng and Huang 2002b). Organic compounds produced by microorganisms such as acetate, citrate, and oxalate were found to increase mineral dissolution rates in laboratory experiments and in the soil (Palmer et al 1991). The production of gluconate promoted dissolution of silicates like albite, quartz, and kaolinite by subsurface bacteria Vandevivere et al 1994).…”

Implications of the evolution of organic acid moieties for basalt weathering over geological time

“…Over 700 lichen substances have been described (Huneck and Yoshimura, 1996). Some of these substances are simple aliphatic carboxylic acids of different (C 1 -C 6 ) chain lengths (such as oxalic, citric, gluconic, pyruvic, malic, succinic, formic, fumaric, and lactic, table 2) and may also be secreted by prokaryotes and by non-lichenized fungi (Palmer andothers, 1991, Gadd, 2000 andreferences herein). Other substances are polyphenolic compounds such as depsides, depsidones, depsones and carotenoids (Huneck and Yoshimura, 1996;Purvis, 2000).…”

Silicates, Silicate Weathering, and Microbial Ecology

“…Fungi, for example, solubilize silicates by the production of both mineral and organic acidity (Eno and Reuzer 1955;Silverman and Munoz 1970;Avakyan, Karavaiko, Mel'nikova, Krutsko, and Ostroushko 1981;Callot, Maurette, Pottier, and Dubois 1987), thus releasing critical nutrients (e.g., Jongmans, van Breeman, Lundstrom, van Hees, Finlay, Srinivasan et al 1997), yet the complexation of released Al 3C reduces phytotoxicity (Kinraide 1991). Fungi have been found to excrete higher concentrations of more effective chelating agents than, for example, bacteria (Palmer, Siebert, and Hirsch 1991). However, bacteria are more proli c and exist in extreme environments that fungi cannot tolerate.…”