Several poly (dimethylsiloxanes) (PDMS) copolymers of dimethylsiloxane (DMS) with ethylene or propylene oxide were tested as artificial carriers for the delivery of oxygen to biological systems. Copolymers with a DMS content of 33% or lower enhanced glucose oxidation by 200% in contrast to the 25% increase produced by the same concentration of perfluorodecalin. When 0.05% of the copolymer with 18% DMS was included in the growth media of Bacillus thuriginensis, the biomass (growth rate) increased 1.5-fold. With 0.1% of this copolymer, actinorhodin production by Streptomyces coelicolor A3 (2) occurred in half the normal time and with an increased yield. In conclusion, these PDMS copolymers are a good alternative to perfluorodecalin as oxygen carriers in biotechnological processes.