Techniques have been developed to obtain Dunaliella chloroplasts and their outer and inner envelopes in high yield. With purified envelopes, we have identified two integral membrane proteins that are specifically induced by low CO2. These two proteins are located in the inner envelope, which is the proposed site for the active dissolved inorganic carbon transporter in unicellular green algae.Key words: algae, carbon concentration mechanism, chloroplast envelopes, dissolved inorganic carbon, Dunaliella, low CO2 induced proteins.