Microorganisms play critical roles in global biogeochemical cycling, and their metabolism is increasingly harnessed for various industrial and environmental applications. Depending on the target processes, microorganisms can be bioprospected from natural or engineered ecosystems that represent the desired process conditions in terms of temperature, pH, salinity or presence of target substrates or contaminants. This presentation gives an overview of our bioprospecting efforts in a wide variety of environments, including extreme hot springs, cold sub-seafloor sediments, acid and saline sulfate soils, alkaline industrial processes, freshwater, and sites contaminated with organic pollutants, such as petroleum hydrocarbons and per- and poly-fluoroalkyl substances (PFAS). The bioprospected microorganisms have included both chemolithoautotrophic and heterotrophic, as well as aerobic and anaerobic bacteria. The microorganisms conduct the oxidation of ferrous iron, reduced sulfur compounds and organic impurities, the reduction of ferric iron and various oxyanions such as nitrate, selenate and sulfate, and reductive dehalogenation. These microbes are promising for use in biohydrogen production, biomining low-grade ores and mining, metallurgical and post-consumer wastes, treatment of industrial effluents and bioremediation. Therefore, harnessing microbial functions and processes for industrial and environmental applications can help the energy, mining, water, and waste sectors become more resilient and environmentally sustainable. Further bioprospecting efforts target microorganisms capable of degrading problematic plastic wastes that have detrimental impacts on a wide variety of ecosystems, and microorganisms that produce precursors for more sustainable bio-based plastic alternatives supporting the transition to a more circular economy.