Microbial proteins and soil carbon sequestration

Abstract

Soil microorganisms catalyze various ecological processes such as nutrient cycling. Microorganisms produce as well as consume greenhouse gases, including CO2. There is a growing interest world wide in sequestering atmospheric C and improving soil properties. Mycorrhizal fungi form a mutualistic association with plants receiving photosynthate from plants. The production of a glycoprotein glomalin by hyphae of AMF is directly linked to soil aggregation and positively correlated with soil aggregate stability. It has been observed that AMF hyphal abundance and soil aggregation are also positively correlated with C and N sequestration. Small (~100 amino acids) cysteine-rich proteins called hydrophobins are expressed only by filamentous saprophytic fungi belonging to ascomycetes and basidiomycetes. Another group of proteins called chaplins are produced by streptomycetes which have shown promise for the carbon sequestration in soils.