Abstract: A cosmetic composition comprising: at least one sunscreen active agent; and, benthic pennate diatom frustules. A method of boosting the SPF of a sunscreen composition. A method of producing a sunscreen by providing an active sunscreen agent, and benthic pennate diatom frustules.

Abstract: A method of extracting frustules from benthic pennate diatoms is disclosed. The method includes culturing benthic pennate diatoms in an industrial biofilm process, wherein in the industrial biofilm process the benthic pennate diatoms are growing on at least one surface in a water-containing compartment and wherein the benthic pennate diatoms forms a biofilm on the at least one surface; harvesting the benthic pennate diatoms from the at least one surface; and extracting the frustules by separating the frustules from organic biomass contained in the benthic pennate diatoms.