(EP830196-A1)      The following are claimed: (A) gas sepn. process, in which a selected gas in a mixed gas stream (MGS) is contacted by an enzyme (which has an active site directly contacting the MGS) and the selected gas is at least partially removed from the MGS; (B) bioreactor comprising a vessel having at least one first wall enclosing an inlet zone and at least one second wall enclosing a second phase zone (SPZ). A portion of the second wall is permeable to at least one selected gas in the inlet zone and retains the second phase in the SPZ. A portion of the second wall also comprises a support surface on which at least one enzyme is fixed, such that a MGS entering the inlet zone contacts enzyme which removes a selected gas from the MGS and passes the selected gas to the SPZ; and (C) bioreactor comprising buoyant beads coated with enzyme, floating on the surface of a condensed fluid phase, in contact with a gas phase (such that the active site of the enzyme is in direct contact with the gas phase). The beads are free to rotate in response to motion in either phase. The bioreactor comprises means for producing motion in at least one phase, such that portions of the beads alternately contact the gas phase and the fluid phase, bringing a selected gas into the condensed fluid phase.    USE -   The process may be used for sepn. of gases and enrichment of gas mixts. and is used, e.g. for treating effluent from smoke stacks, to process gases such as carbon dioxide, hydrogen sulphide, methane, ozone or nitrogen oxides.    ADVANTAGE -   The process allows prodn. of very large vols. of gas. The sepn. appts. may be located at or near the site of final use, reducing necessary transportation.    (US6143556-A)      The following are claimed: (A) gas sepn. process, in which a selected gas in a mixed gas stream (MGS) is contacted by an enzyme (which has an active site directly contacting the MGS) and the selected gas is at least partially removed from the MGS; (B) bioreactor comprising a vessel having at least one first wall enclosing an inlet zone and at least one second wall enclosing a second phase zone (SPZ). A portion of the second wall is permeable to at least one selected gas in the inlet zone and retains the second phase in the SPZ. A portion of the second wall also comprises a support surface on which at least one enzyme is fixed, such that a MGS entering the inlet zone contacts enzyme which removes a selected gas from the MGS and passes the selected gas to the SPZ; and (C) bioreactor comprising buoyant beads coated with enzyme, floating on the surface of a condensed fluid phase, in contact with a gas phase (such that the active site of the enzyme is in direct contact with the gas phase). The beads are free to rotate in response to motion in either phase. The bioreactor comprises means for producing motion in at least one phase, such that portions of the beads alternately contact the gas phase and the fluid phase, bringing a selected gas into the condensed fluid phase.    USE -   The process may be used for sepn. of gases and enrichment of gas mixts. and is used, e.g. for treating effluent from smoke stacks, to process gases such as carbon dioxide, hydrogen sulphide, methane, ozone or nitrogen oxides.    ADVANTAGE -   The process allows prodn. of very large vols. of gas. The sepn. appts. may be located at or near the site of final use, reducing necessary transportation.