Over the past few years the idea of living photosynthetic materials has advanced from concept to reality. This work outlines the improvements made in the immobilisation of the thermotolerant acidophile Cyanidium caldarium (Tilden) Geitler SAG 16.91 within porous and transparent silica gels with the view to targeting photochemical materials that can be used to mitigate rising CO2 emissions. Our results suggest that the immobilised cells are autofluorescent for at least 75 days post encapsulation and can maintain a steady oxygen production rate over a similar timeframe corroborating the viability and physiological activity of silica immobilised C. caldarium. (C) 2011 Elsevier Inc. All rights reserved.