The Gram stain is a differential stain, which allows most bacteria to be divided into two groups, grampositive bacteria and gram-negative bacteria. Morphological characters of isolates were observed by smears from colonies up to 10 days, stained by Gram’s method as described by Hucker and Conn (1923).Microscopic characterization was done by cover slip culture method (Kawato and Sinobu, 1959). The mycelium structure, color and arrangement of conidiospore and arthrospore on the mycelium were observed through the oil immersion (1000×, Olympus) microscope. The observed structure was compared with Bergey’s manual of Determinative Bacteriology, ninth edition (2000) and the organism was identified. Colonies were identified on the basis of their colony morphology and color (Shirling and Gottlieb, 1966).
Color of aerial mycelium was determined from mature, sporulating aerial mycelia of the actinomycetes colonies on starch-casein agar media (Pridham, 1964).