Preservation of H2 production activity in nanoporous latex coatings of Rhodopseudomonas palustris CGA009 during dry storage at ambient temperatures

摘要

To assess the applicability of latex cell coatings as an u27off-the-shelfu27 biocatalyst, the effect of osmoprotectants, temperature, humidity and O(2) on preservation of H(2) production in Rhodopseudomonas palustris coatings was evaluated. Immediately following latex coating coalescence (24 h) and for up to 2 weeks of dry storage, rehydrated coatings containing different osmoprotectants displayed similar rates of H(2) production. Beyond 2 weeks of storage, sorbitol-treated coatings lost all H(2) production activity, whereas considerable H(2) production was still detected in sucrose- and trehalose-stabilized coatings. The relative humidity level at which the coatings were stored had a significant impact on the recovery and subsequent rates of H(2) production. After 4 weeks storage under air at 60% humidity, coatings produced only trace amounts of H(2) (0-0.1% headspace accumulation), whereas those stored at u3c 5% humidity retained 27-53% of their H(2) production activity after 8 weeks of storage. When stored in argon at u3c 5% humidity and room temperature, R. palustris coatings retained full H(2) production activity for 3 months, implicating oxidative damage as a key factor limiting coating storage. Overall, the results demonstrate that biocatalytic latex coatings are an attractive cell immobilization platform for preservation of bioactivity in the dry state.