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Solid support membrane‐aerated catalytic biofilm reactor for the continuous synthesis of ( S )‐styrene oxide at gram scale
Author(s) -
Halan Babu,
Letzel Thomas,
Schmid Andreas,
Buehler Katja
Publication year - 2014
Publication title -
biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.144
H-Index - 84
eISSN - 1860-7314
pISSN - 1860-6768
DOI - 10.1002/biot.201400341
Subject(s) - bioprocess , yield (engineering) , styrene oxide , chemical engineering , membrane reactor , biofilm , catalysis , membrane , styrene , chemistry , biomass (ecology) , materials science , organic chemistry , biochemistry , copolymer , biology , bacteria , engineering , metallurgy , genetics , polymer , oceanography , geology
Catalytic biofilms minimize reactant toxicity and maximize biocatalyst stability in selective transformations of chemicals to value‐added products in continuous processes. The scaling up of such catalytic biofilm processes is challenging, due to fluidic and biological parameters affording a special reactor design affecting process performance. A solid support membrane‐aerated biofilm reactor was optimized and scaled‐up to yield gram amounts of ( S )‐styrene oxide, a toxic and instable high value chemical synthon. A sintered stainless steel membrane unit was identified as an optimal choice as biofilm substratum and for high oxygen mass transfer. A stable expanded polytetrafluoroethylene (ePTFE) membrane was best suited for in situ substrate delivery and product extraction. For the verification of scalability, catalytic biofilms of Pseudomonas sp. strain VLB120ΔC produced ( S )‐styrene oxide to an average concentration of 390 mM in the organic phase per day (equivalent to 24.4 g L aq –1 day –1 ). This productivity was gained by efficiently using the catalyst with an excellent product yield on biomass of 13.6 g product g biomass –1 . This product yield on biomass is in the order of magnitude reported for other continuous systems based on artificially immobilized biocatalysts and is fulfilling the minimum requirements for industrial biocatalytic processes. Overall, 46 g of ( S )‐styrene oxide were produced and isolated (purity: 99%; enantiomeric excess [ee]: >99.8%. yield: 30%). The productivity is in a similar range as in comparable small‐scale biofilm reactors highlighting the large potential of this methodology for continuous bioprocessing of bulk chemicals and biofuels.