الفهرس 
Monuments and microbesOnly 14 pages are availabe for public view
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Abstract
The incidence and damaging ability of bacteria and
fungi on ancient stone monuments were detected by
different isolation methods. Samples were collected from
seven different sites; Seti Ι tomb at Luxor, Senusret Ι
obelisk of Al Mattaryia district, Giza pyramid complex and
related tomb, store of National Museum of Egyptian
Civilization (NMEC), Mosque of Judge Abd El Basset
(Gamaliya), The Roman Amphitheatre of Alexandria and
Ismailia Museum of Antiquities.
Qualitative assay was carried out for all isolates to
select the actually stone inhabiting isolates by subculturing
on CaCO3 mineral medium. All actinomycetal isolates were
capable to colonize stone material while 45.8% and 38.9%
of bacterial and fungal isolates respectively were stone
colonizers.
Quantitative assay was performed to select the most
potent degrading isolates. The results revealed that the
highest percentage of degradation by actinobacterial isolate
was 28.85%, while the degradation percentage for the other
isolates ranged between 2.6% to 25.6% .The highest bacterial
degradation was 20.9% of the total amount of CaCO3 and
other isolates recorded degradation values from 5.3% to
18.9%, also the highest fungal degradation was 23.3% and
the other isolates ranged from 11.9% to 21.7%.
Acid and pigment production assays revealed that all
selected isolates that were capable of growing on CaCO3
medium, were acid producers, while 33.3% and 22.2 of
actinobacterial and fungal isolates were pigment producers
and none of bacterial isolates were pigment producer.
Antimicrobial activity of natural and chemical
compounds against these isolates revealed that cinnamon,
clove, thyme oil and all tested chemical compounds (para
chloro meta cresol, cetrimonium and tetra ethyl ammonium
bromide) has abundant activity against tested isolates,
while camphor, peppermint, basil and lavender oil had no
inhibitory effect on the tested isolates.
The minimum inhibitory concentration of PCMC,
TEAB and cetrimonium against bacterial isolates were 2.5
g/l, while 10 g/l for cinnamon, clove and thyme respectively.
PCMC, TEAB and cetrimonium MICs against actinobacteria
were 5, 0.6 and 1 g/l, while were 5 g/l for all natural
compounds. The minimum inhibitory concentration of
para,meta chloro cresol(PCMC) was 1.25mg/ml, while 5 g/l
of cetrimonium and 2.5 g/l of tetra ethyl ammonium
bromide was effective against tested fungal isolates.
Minimum inhibitory concentration of clove and thyme
were 10 g/l, while cinnamon was 5 g/l.
The most potent isolates from each group were
identified as Bacillus safensis (MH370265), Streptomyces
rochei (MH370266) and Cladosporium herbarum and were
selected for further experiments.
Infected models with most potent strains were
constructed as a simulation of deteriorated monuments.
Incubated stones with either Bacillus safensis ,
Streptomyces rochei or Cladosporium herbarum after one
month of incubation showed different signs of deterioration
that were visually observed including discoloration, dark
pigmentation, turbidity and powdering. Inoculated stones
exhibited changes in all physical characters. Higher
changes were detected with Streptomyces rochei compared
with Bacillus safensis and Cladosporium herbarum, where
stone strength was reduced by 41.9%, 27.7% and 23.3% for
Streptomyces rochei, Cladosporium herbarum and Bacillus
safensis respectively. In addition, the porosity was reduced
by 49.4% for Streptomyces rochei and 6.1% and 25.7% for
Bacillus safensis and Cladosporium herbarum respectively.
Scanning electron microscope imaging showed
disintegration of calcite crystal, as well as loss of binding
materials between grains, also small fissures and cavities
were found around microbial biofilm due to the microbial
growth. In addition, fungal, actinobcterial mycelium and
also bacilli cells were found within stone. EDX
microanalysis of stone samples revealed that, the control
consisted of calcium (Ca), silicon (Si), sodium (Na),
aluminum (Al), carbon (C) and (O) oxygen while, infected
samples analysis demonstrated reduction of calcium
percent which is the main constituent of limestone, on
contrary sodium and chlorine increased and also new
elements appeared like iron and sulfur element indicating
new salt formation.
Simulation of treatment and conservation
experiments of stones by MICs of chemical and natural
compounds demonstrated that cetrimonium (0.6 g/l), tetra
ethyl ammonium bromide (0.6 g/l) and PCMC (0.6 g/l)
inhibited B.safensis, S.rochei and C.herbarum growth by
100%, while cinnamon oil (1 g/l) inhibited 99.8% and
99.2% of B.safensis and C. herbarum respectively, while
cinnamon (5g/l) inhibited 99.7% of S.rochei growth when
used as a treatment after infection.
For protection or conservation assessment, tetra ethyl
ammonium bromide (0.6 g/l) and PCMC (0.6 g/l) inhibited
98.9% of S.rochei and C.herbarum cells respectively, while
cetrimonium (0. 6 mg/ml) inhibited B.safensis growth by
99.6%. Cinnamon oil (1 g/l) inhibited 99.1 and 91.1 of
B.safensis and C.herbarum respectively, while cinnamon
(5g/l) inhibited S.rochei by 93.1%.