Process for treating an effluent gas containing CO2 with Carbonic anhydrase having increased temperature stability

Abstract

The present invention relates to polynucleotide and polypeptide sequences of novel carbonic anhydrase variants having increased stability under high temperature conditions compared to native carbonic anhydrase.

1 . A process for treating an effluent gas containing CO 2 , comprising:
 providing a bioreactor, the bioreactor comprising:   a reaction chamber for receiving an aqueous solution;   a liquid inlet in fluid communication with the reaction chamber for providing the reaction chamber with the aqueous solution;   a gas inlet connected to the reaction chamber for providing the effluent gas to be treated into the reaction chamber in order to contact the aqueous solution;   a liquid outlet in fluid communication with the reaction chamber for releasing an ion-rich solution;   a gas outlet in fluid communication with the reaction chamber to release a treated gas;   providing within the reaction chamber carbonic anhydrase or any functional derivative, fragment or analogue thereof, with increased stability under high temperature conditions, for catalyzing the reaction CO 2 +H 2 O H + +HCO 3   − , to produce the treated gas and the ion-rich solution.   
     
     
         2 . The process of  claim 1 , wherein the carbonic anhydrase is within the aqueous solution. 
     
     
         3 . The process of  claim 1 , wherein the gas inlet comprises gas bubbling means connected to the reaction chamber for bubbling the effluent gas to be treated into the aqueous solution thereby dissolving the gas into the aqueous solution. 
     
     
         4 . The process of  claim 1 , comprising controlling the pressure within the reaction chamber. 
     
     
         5 . The process of  claim 4 , wherein the ion-rich solution is released by pressure. 
     
     
         6 . The process of  claim 1 , wherein the carbonic anhydrase is provided on or in substrates that are in suspension within the aqueous solution. 
     
     
         7 . The process of  claim 6 , comprising providing a filter in between the reaction chamber and the liquid outlet, the filter having pores with a smaller diameter than a diameter of the substrates for separating the substrates from the ion-rich solution. 
     
     
         8 . The process of  claim 7 , wherein the filter is constructed to enable ultrafiltration or microfiltration. 
     
     
         9 . The process of  claim 6 , wherein further comprising a retention device for retaining the substrates in the reaction chamber. 
     
     
         10 . The process of  claim 6 , wherein the carbonic anhydrase are immobilized onto the substrates. 
     
     
         11 . The process of  claim 10 , wherein the carbonic anhydrase are covalently bonded onto the supports. 
     
     
         12 . The process of  claim 6 , wherein the substrates are solid polymer particles. 
     
     
         13 . The process of  claim 6 , wherein the supports are composed of nylon, polystyrene, polyurethane, polymethylmethacrylate, or functionalised silica gel. 
     
     
         14 . The process of  claim 6 , wherein the substrates comprise porous substrates and the carbonic anhydrase are entrapped in the porous substrates. 
     
     
         15 . The process of  claim 14 , wherein the porous substrates are made of organic or inorganic material. 
     
     
         16 . The process of  claim 14 , wherein the porous substrates comprise particles composed of an insoluble gel, silica, alginate, alginate/chitosan or alginate/carboxymethylcellulose. 
     
     
         17 . The process of  claim 6 , wherein the substrates comprise a network and the carbonic anhydrase are chemically linked with the network. 
     
     
         18 . The process of  claim 17 , wherein the network is a PEG network or an albumin network. 
     
     
         19 . The process of  claim 6 , wherein the substrates comprise particles of 0.005 μm to 0.1 μm in size. 
     
     
         20 . The process of  claim 6 , wherein the substrates comprise particles of 1 mm to 9 mm in diameter. 
     
     
         21 . The process of  claim 1 , wherein the bioreactor is a packed tower. 
     
     
         22 . The process of  claim 21 , wherein the packed tower comprises:
 a bottom chamber having the gas inlet and the liquid outlet;   an upper chamber having the liquid inlet and the gas outlet; and   the reaction chamber is disposed between the bottom chamber and the upper chamber and is in fluid communication therewith, the reaction chamber being packed with a plurality of solid supports; and   the process comprising the further steps of:   a) supplying the liquid inlet of the upper chamber with the aqueous solution while supplying the gas inlet of the bottom chamber with the effluent gas, the gas flowing into the reaction chamber;   b) directing the aqueous solution into the packed reaction chamber to contact the effluent gas with the aqueous solution and promote absorption of the CO 2  in the aqueous solution, and thereby allowing the carbonic anhydrase to catalyze the reaction of the diffused CO 2 ;   c) evacuating from the liquid outlet of the bottom chamber the ion-rich solution containing the H +  ions and HCO 3   −  ions produced in the reaction chamber and evacuating from the gas outlet of the upper chamber the treated gas.   
     
     
         23 . The process of  claim 22 , wherein the supports support the carbonic anhydrase within the reaction chamber. 
     
     
         24 . The process of  claim 23 , wherein the carbonic anhydrase is immobilised onto a surface of the supports. 
     
     
         25 . The process of  claim 1 , wherein the bioreactor comprises:
 at least one cassette provided with a reactive material comprising the carbonic anhydrase;   the reaction chamber having at least two spaced-apart baffle walls in the reaction chamber for regulating the flow of the effluent gas therein, and having an opening for removably inserting therein one of the at least one cassette; and   mounting means for mounting the one cassette in the reaction chamber spaced-apart from the two baffle walls;   whereby the one cassette being disposed between the two spaced-apart baffle walls causes the effluent gas to flow in a zigzag pattern.   
     
     
         26 . The process of  claim 1 , wherein the carbonic anhydrase has increased stability above 37° C., above 55° C., above 60° C., above 62.5° C., above 65° C., or between 25° C. and 70° C. 
     
     
         27 . The process of  claim 1 , wherein after 2 hours at 60° C. the carbonic anhydrase presents a residual activity above 85%, above 95% or of 100%. 
     
     
         28 . The process of  claim 1 , wherein after 2 hours at 62.5° C. the carbonic anhydrase presents a residual activity above 15%, above 60%, above 68%, above 92% or of 100%. 
     
     
         29 . The process of  claim 1 , wherein after 2 hours at 65° C. the carbonic anhydrase presents a residual activity above 7%, above 76% or above 88%. 
     
     
         30 . An enzymatic process for treatment of a fluid by catalyzing reaction CO 2 +H 2 O H + +HCO 3   −  with carbonic anhydrase or any functional derivative, fragment or analogue thereof, with increased stability under high temperature conditions, the process comprising:
 feeding the fluid into a reaction chamber; 
 allowing the reaction to occur within a liquid in the presence of the carbonic anhydrase, to produce a gas stream and a liquid stream; and 
 releasing the gas stream and the liquid stream from the reaction chamber.