Bacterial biomineralization: new insights from Myxococcus-induced mineral precipitation - Tufas and Speleothems: Unravelling the Microbial and Physical Controls - page 30

Bacterial biomineralization: new insights from
Myxococcus-induced mineral precipitation

MARIA TERESA GONZ ´ LEZ-MU ˜ OZ 1 , CARLOS RODRIGUEZ-NAVARRO 2 *,
FRANCISCA MART ´ NEZ-RUIZ 3 , JOSE MARIA ARIAS 1 , MOHAMED L. MERROUN 4 &
MANUEL RODRIGUEZ-GALLEGO 2
1 Departamento de Microbiolog´a, Universidad de Granada, Fuentenueva s/n, 18002,
Granada, Spain
2 Departamento de Mineralog´a y Petrolog´a, Universidad de Granada, Fuentenueva s/n,
18002, Granada, Spain
3 Instituto Andaluz de Ciencias de la Tierra, CSIC - Universidad de Granada, Fuentenueva
s/n, 18002, Granada, Spain
4 Institute of Radiochemistry, Forschungszentrum Dresden-Rossendorf, D-01314,
Dresden, Germany; Present address: Departamento de Microbiolog´a, Universidad
de Granada, Granada, Spain
*Corresponding author (e-mail: [e-mail])

Abstract: Bacteria have contributed to the formation of minerals since the advent of life on Earth.
Bacterial biomineralization plays a critical role on biogeochemical cycles and has important tech-
nological and environmental applications. Despite the numerous efforts to better understand how
bacteria induce/mediate or control mineralization, our current knowledge is far from complete.
Considering that the number of recent publications on bacterial biomineralization has been over-
whelming, here we attempt to show the importance of bacteria - mineral interactions by focusing
in a single bacterial genus, Myxococcus, which displays an unusual capacity of producing minerals
of varying compositions and morphologies. First, an overview of the recent history of bacterial
mineralization, the most common bacteriogenic minerals and current models on bacterial biomi-
neralization is presented. Afterwards a description of myxobacteria is presented, followed by a
section where Myxococcus-induced precipitation of a number of phosphates, carbonates, sulphates,
chlorides, oxalates and silicates is described and discussed in lieu of the information presented in
the first part. As concluding remarks, implications of bacterial mineralization and perspectives
for future research are outlined. This review strives to show that the mechanisms which control
bacterial biomineralization are not mineral- or bacterial-specific. On the contrary, they appear to
be universal and depend on the environment in which bacteria dwell.

Microbes are considered the oldest living creatures
on Earth (Schopf 1993). Although there is still
controversy as to when, how and where they first
appeared (between 3550 - 3800 Ma) (Mojzsis et al.
1996; Altermann & Kazmierczak 2003; Garc ´ a-
Ruiz et al. 2003), there is compelling evidence
that microbes have been closely related to the
solid phases they were forced to live with over the
last c. 3.5 billion years: that is, minerals (Ehrlich
2002). That long-term relationship has been extra-
ordinarily productive. It has contributed to the
shaping of the Earth surface (and near-subsurface)
sediments and rocks, and to the evolution of the
chemistry and composition of the oceans (Banfield
et al. 1998) and of the Earth atmosphere (Kasting
& Siefert 2002; Wiechert 2002). It is believed for

instance that cyanobacteria have aided in the for-
mation of mineralized stromatolites since the
Precambrian (Arp et al. 2001; Bosak & Newman
2003), their photosynthetic activity thus contri-
buting to atmosphere oxygen increase and CO 2
budgeting by carbonate precipitation since c. 2.15
billion-years-ago (Buick 1992). Fe(II)-oxidizing
bacteria may have been responsible for the for-
mation of Precambrian iron formations (Konhauser
et al. 2002) and may have had an important impact
on ancient metal cycling. Microbes are assumed to
have played a major role on evolution during snow-
ball Earth episodes when it is suspected that only
extremophiles could survive and repopulate the
planet (Kerr 1997). Examples of the role of bacteria
in Earth History are abundant since they have been