Abstract:
A study was conducted to assess the ability of Streptomyces isolates to grow under pH conditions other than their original environmental pH. The study involved isolation of Streptomyces from soils in four different locations in Magadu area, Morogoro, Tanzania. The Streptomyces were isolated using the starch-casein agar medium and subsequently grown under different simulated pH conditions, both buffered and unbuffered, in the oat-meal medium. The results of the isolation revealed that the soils had a diversity of Streptomyces isolates, growth of each of which was favoured by particular pH conditions. For the soils with an original pH of 5.0 the growth of two cultures increased and one seemed to show a peak growth when the pH was decreased to 4.5. Others did not show much change in growth. The soils which had a pH of 6.3 had three cultures whose growth was improved when pH wasincreased beyond pH 6.3. Others were almost unchanged. Almost all cultures from soils of pH 7.0 had their growth decreased when pH of the growth medium was increased pH 7.0. The Streptomyces isolates from soils with an original pH of 8.1 showed little change in growth as pH was altered. The colors of the mature colonies that formed when theStreptomyces were grown at various pH levels were cream, white, blue, gray, brown and red, with the cream color being the dominant one. When results of growth of Streptomyces on an unbuffered medium were compared to that on buffered medium, there was generally poor growth of Streptomyces with the latter medium. It was concluded that these Streptomyces which would grow at the buffered pH levels were those that were adapted to those pH conditions. However the unbuffered medium could allow the development of micro-sites with different pH and wider range of pH values conducive to growth of a wider variety of strains.
