Abstract:

Biological soil crusts （BSCs） are integral to desert ecosystems， facilitating the conversion of organic carbon to inorganic forms through a diverse array of carbon-degrading strains， thereby promoting the decomposition of organic matter and the carbon cycle in desert ecosystems. This study focused on BSCs from the Shapotou sand-fixing vegetation area， aiming to screen and identify functional strains with the ability to degrade different types of carbon sources and to evaluate their enzyme activities. The results showed that strains D7 and D8 had the highest amylase activity， at 1.52 U·mL^-1 and 1.69 U·mL^-1， respectively； strain G5 had the highest pectinase activity， at 1.01 U·mL^-1； strains X2 and X5 had the highest cellulase activity， at 1.59 U·mL^-1 and 2.19 U·mL^-1， respectively. Strain M1 displayed significant lignin peroxidase activity as determined by the aniline blue decolorization assay. Molecular biological identification revealed that these strains primarily belong to Pantoea alhagi （D7、D8、X5）， Bacillus subtilis （X2）， Erwinia piriflorinigrans （G5）， and Cupriavidus respiraculi （M1）.

Key words: biological soil crusts, carbon-degrading strains, carbon cycle, desertification