Browsing by Author "Kibret, Mulugeta"

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    Aerobic Heterotrophic Bacterial Flora of one of Shalla Hot Springs
    (Addis Ababa,University, 1991-06) Kibret, Mulugeta; A. Gashe, Berhanu (PhD)
    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.