DBPapers

ECOLOGICAL EFFECTS OF MICROBIALLY-TREATED HYDROXYAPATITE

AUTHOR/S: N. VASSILEV, A. REYES, D. ALTMAJER, M. SERRANO, D. SANCHEZ, M. VASSILEVA
Sunday 1 August 2010 by Libadmin2010

10th International Multidisciplinary Scientific GeoConference - SGEM2010, www.sgem.org, SGEM2010 Conference Proceedings/ ISBN 10: 954-91818-1-2, June 20-26, 2010, Vol. 2, 521-529 pp

ABSTRACT

Current management of phosphate-bearing resources (mainly rock phosphates, RPs),
which in fact are finite non-renewable sources, is quite far from the principles of
sustainability and may cause an escalating price increase mainly because of increases in
RP-processing costs. One of the most studied approaches in solubilization of insoluble
phosphates is the biological treatment of phosphate-bearing materials. In this work, we
propose a microbial extraction of phosphate from insoluble inorganic natural sources as
a less expensive and lower energy technique compared with the conventional chemical
processes. Experiments were based on fermentation processes using both synthetic
media and agro-wastes derived from the olive oil producing and sugar beet processing
industries. Further introduction of the resulting products into plant-soil systems was also
studied. These biotechnological processes and respective products demonstrated a
number of advantages in several directions:
A) Simultaneous phosphate solubilization and enzyme production in solid-state
fermentation conditions
a. Chitinase
b. Phosphatase
c. Manganese peroxidase
B) Improvement of soil structure
C) Stimulation of soil enzyme activities
D) Remediation of heavy metal contaminates sites
E) Biological control of phyto-pathogenic fungi
It is interesting to note that in fermentation conditions the enzyme production is
normally enhanced in presence of insoluble phosphates. Combined with standard
techniques for nutrient medium and process parameters optimization, it is possible to
achieve high production rates. On the other hand, the functions B to E are closely
related to plant growth promotion particularly in typical Mediterranean soils
characterized by low phosphate concentration and low organic matter. The results of our
studies demonstrate the immense potential of bio-based alternative methods for
treatment of natural P-bearing materials and their ecological profile.

Keywords: Natural P-bearing materials; Microbial treatment; Fermentation experiments; Introduction into soil-plant systems; Simultaneous activities