Abstract
Biocrusts, as the dominant green strips in arid continents, potentially
sever as a useful tool for immobilizing Pb in contaminated land under
extreme constraints such as water resource. Artificially created
biocrusts ensure the expansion of biocrusts in the short period. In this
study, Microcoleus steenstrupii and montmorillonite (MMT) were
used to construct artificial cyanobacterial biocrusts (ACBs) on the
surface of Pb-containing dunes and cultured in compliance with the water
conditions of the arid climate. Results suggested that MMT induced bulk
productions of protective substances such as exopolysaccharides (EPS)
and soluble proteins and reduced the overall oxidative damage of ACBs
weakened by malondialdehyde. Biomineralization was identified as a
possible pathway for ACBs to diminish Pb(II) effectiveness. The inoculum
not only converted Pb(II) into Pb 3(CO
3) 2(OH) 2 and Pb
5(PO 4) 3OH, but also
triggered the evolution of different cyanosphere communities that each
accomplished a complicated biomineralization and precipitation process.
This study revealed the feasibility of remediation of Pb-contaminated
surfaces and provided an effective approach for the utilization of
wasted land in arid regions.