Aerobic Heterotrophic Bacterial Flora of one of Shalla Hot Springs
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Date
1991-06
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Addis Ababa,University
Abstract
Four sites i n one ot the ho t.. springs ot Shalla were
selec ted for the study. The wate r fr om t he sites me rge to form
a s t ream whic h forms a te mperature gradient . In this study f our
media we r e compa1;' ed tOI? the c ultivation and i solation o f
aerobic heter otrophic bac ter i a. The pH of the ho t spring was
8. 7 with a temperature of 9G-56'C . The f o rmulated Illedia were
adjusted to pH values o f 7 .0-13 .0. Howeve r , hlgh count s of
bacte ria (lxlOl - 7x lOt c f u/ mll was only r egis tered when the pH
was ad juste d be twee n 8.0 and 9.0. A medi um containing normal
conce ntra tion of Trypton Soya Agar (TSA) was effective i n
s uppo rt ing the growth of bacteria t han a med i um c on taining one quarte
r strength of TSA o r supplement o f trace minerals.
Replaci ng trac e minerals wi th hot s pri ng "" ate r improved the
total numbe r of bacteria irowlng and also the number or
i so l ates.
Thcrmophl1ea were nume r o us (l:d Ol __ 1x l 0' clu/rol) than
the rmo tol e r ants (2xlOl_2xl O( c fu/ml) at all sites . The
population of Bac illus brevis , Bac illus spbae ricu8, Bacillus
s t e arothermQphilu3 and Mi c r ococcus sp. was found to be low at
l owe r e nvironmental temperatures than at hliher environmental
temperatures .
In t he course of t hi s s tudy a total of 44
micro organisms we r e isolated and char.cterlJ1ed. Twenty nine
we r e identified to the s pecies level and were touftd to be
membe r s o f genus Baci llus .
Three isolates were Cram-positive cocci id e ntified
t o the ge nus l eve l - Micrococcus. The r e main i ng 12 isolates
were ei ther Gram-positi ve , filame ntous or no n- filamentous r od s
wh ich need a deta il ed bioc he mi c al analysis for i denlifi c ation .
To identify if any o f the isolates may have
industrial applications , they we r e c hecked f o r product i on o f
amylase and protease . Fifteen o f the isolates produced
protease, 18 amylase and eleven I-roduced both amylase and
protease.
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Keywords
Aerobic Heterotrophic Bacteri Al Flora