The effects of nitrogen source, the concentration of spore suspension and dissolved oxygen tension on morphology and antibiotic production of RhizPous chinesis 12 were investigated. The nitrogen source greatly affected fungal morphology and antibiotic production. In the medium containing corn steep liquor, pellets were formed and highest antibiotic production (6328.0 U ml(-1)) was achieved. With a concentration of spore suspension of 10(7) spores per ml, the highest antibiotic production was obtained and pellets were formed. In addition, improvement of dissolved oxygen tension was favourable for antibiotic production and pellets formation. (C) 2002 Elsevier Science Ltd. All rights reserved.