Designer xylanosomes: protein nanostructures for enhanced xylan hydrolysis

This work reports the successful design, construction, and application of multi-functional, self-assembling protein complex, termed xylanosomes. Using the architecture of cellulosomes as template, these structures were designed specifically for hemicellulose hydrolysis. Four different xylanosomes were developed, with up to three different hemicellulase activities combined into a single structure. Each xylanosome was composed of two native or chimeric hemicellulases and tested on wheat arabinoxylan or destarched corn bran for enzymatic hydrolysis. After 24-h incubation, soluble sugars released from arabinoxylan increased up to 30 % with xylanosomes containing a xylanase and bi-functional arabinofuranosidase/xylosidase over the corresponding free, unstructured enzymes. Additionally, xylanosomes with a xylanase and a ferulic acid esterase removed between 15 and 20 % more ferulic acid from wheat arabinoxylan than free enzymes. Furthermore, xylanosomes exhibited synergy with cellulases on destarched corn bran, suggesting a possible use of these nanostructures in cellulose hydrolysis.