Aerial mycelium formation in rare thermophilic Actinobacteria on media solidified with agar and gellan gum

Abstract

Abstract This study investigated aerial mycelium formation in 12 isolates of rare thermophilic Actinobacteria from Indonesia on four different media (International Streptomyces Project ISP 1, ISP 2, ISP 3, and Bennett’s solidified with agar and gellan gum). The results from media solidified with agar showed that aerial mycelium formation was observed on 9 isolates as follows: 3 isolates on ISP 1 agar (Amycolatopsis and Microbispora); 3 isolates on ISP 2 agar (Amycolatopsis and Microbispora); 9 isolates on ISP 3 agar (Actinoallomurus, Amycolatopsis, Microbispora, Thermobispora, and Streptoalloteichus); and 2 isolates of Amycolatopsis on Bennett’s agar. Aerial mycelium formation was not observed in 3 isolates (Microbispora and Nocardia) on all media solidified with agar. The results from media solidified with gellan gum showed that aerial mycelium formation was observed in all 12 isolates as follows: 8 isolates on ISP 1 gellan gum (Amycolatopsis, Microbispora, Nocardia and Thermobispora); 5 isolates on ISP 2 gellan gum (Amycolatopsis, Microbispora, and Nocardia); 11 isolates on ISP 3 gellan gum (Actinoallomurus, Amycolatopsis, Microbispora, Nocardia, Thermobispora, and Streptoalloteichus); and 5 isolates on Bennett’s agar (Amycolatopsis, Microbispora, Nocardia, and Streptoalloeichus). These results indicate that the media solidified with gellan gum induced aerial mycelium formation in larger number of rare thermophilic Actinobacteria isolates compared to media solidified with agar.