. The overall commercial goal of the proposed program is to enable the discovery and development of new anticancer drugs by developing methods and processes for the production of halophilic microorganisms and their natural product chemicals. This project seeks to establish and screen a library of several thousand strains of heterotrophs from hypersaline environments. Moderately halophilic microorganisms, which grow optimally in greater then 10 percent salinity, not 3.5 percent salinity marine seawater, are diverse and include many not found in normal marine and terrestrial environments. They potentially represent a large, untapped source of unique natural products. Using both traditional and novel, marine-derived media, a variety of bacterial groups will be targeted for isolation, including actinomycetes and animal symbionts. Extracts of bacterial isolates will be tested for antitumor activities, and bioactive extracts and compounds will be biologically and chemically characterized. The project is innovative in that microbial cultivation will target hypersaline sources of microorganisms, especially actinomycetes and animal symbionts, will use high salt media with altered concentrations of halides, and will use marine sources both for growth and as precursor substrates for secondary metabolite production.