Abstract:
Actinomycetes are best producers of bioactive therapeutic compounds (secondary metabolites)
namely antibiotics. Actinomycetes are found in many habitats, such as soil, freshwater, seawater, cold- warm-blooded animals, composts as well as insect guts (termite gut). In the current
studyIsolation, Screening and Identification ofBroad Spectrum Antibiotic Producing
Actinomycetes from Compost and Termite Gut in Delgi Area, Takussa Woreda, Central
GondarZone, Ethiopia. Then isolation, screening, identification and characterization of
actinomycetes was carried out.The isolates were identified and characterized usingantimicrobial
activities, cultural, morphological, and physiological and biochemical tests and found to be
classified under the genusStreptomyces.Selected isolates were testedfor their antimicrobial
activities using primary screening test against reference clinical isolates. These test
microorganisms include Staphylococcus aureus, Escherichia coli, Shigella dysenteriae,
Salmonella typhi,Citrobacterspp and Candidaalbicans. Among all suspected actinomycetes only
six isolates IC1, IC2, IC3, IC5, II1andII2 were able to inhibitgrowth at least one among the six of
tested pathogens. IC1, IC2, IC3 and IC5 which account 66.7% were isolated from compost
sample and II1 and II2 which account 33.3% were obtained from termite gut. From the result of
antimicrobial bioassay in secondary screening, the crude extract showed different diameter zone
of inhibition, larger inhibition zone of diameter was observed by isolate II2 (24± 1.27 mm)
crude extract against clinical isolate S.aureus and the least inhibition zone was exhibited by
isolate IC1 (9±0.43mm) crude extract against E. coli. The optimum growth conditions of
actinomycetes isolated from compost and termite gut at different were studied. Maximum growth
was recorded at pH 7 for isolate IC1, IC5 and II1 and II2 and pH 9 for isolate IC2 and IC3,
respectively. The optimum temperature for maximum growth for isolates IC1, IC5, II1 and II2
was 30°C, while optimum temperature for maximum growth for isolates IC2and IC3 was 37°C.
All isolates were grown in a media supplemented with 5% and 7% a salt concentration except
isolates IC5 and II2 that fail to grow at7% salt concentration. The isolates were found to grow on
a wider range of carbon- nitrogen sources with little variations. All the isolates were able to
utilize D-glucose, D-galactose, sucrose, peptone and L-Arganine. In addition, all of them could
not utilize cellulose and (NH4)2SO4. The data obtained in current study showed that the isolated
actimomycetes have great broad spectrum potential to act against Gram positive and Gram
negative pathogenic bacteria as well as fungi. It is also recommended that isolates should be
further tested against different test pathogenic microorganisms to fully understand their
antimicrobial potential
