title: Catalytic biofilms on structured packing for the production of glycolic acid.
abstract: While structured packing modules are known to be efficient for surface wetting and gas-liquid exchange in abiotic surface catalysis, this model study explores structured packing as a growth surface for catalytic biofilms. Microbial biofilms have been proposed as self-immobilized and self-regenerating catalysts for the production of chemicals. A concern is that the complex and dynamic nature of biofilms may cause fluctuations in their catalytic performance over time or may affect process reproducibility. An aerated continuous trickle-bed biofilm reactor system was designed with a 3 L structured packing, liquid recycling and pH control. Pseudomonas diminuta established a biofilm on the stainless steel structured packing with a specific surface area of 500 m2 m-3 and catalyzed the oxidation of ethylene glycol to glycolic acid for over two months of continuous operation. A steady-state productivity of up to 1.6 gl-1h-1 was achieved at a dilution rate of 0.33 h-1. Process reproducibility between three independent runs was excellent, despite process interruptions and activity variations in cultures grown from biofilm effluent cells. The results demonstrate the robustness of a catalytic biofilm on structured packing, despite its dynamic nature. Implementation is recommended for whole-cell processes that require efficient gas-liquid exchange, catalyst retention for continuous operation, or improved catalyst stability.
authors: School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney NSW 2052, Australia.
authors: Xuan Zhong
authors: XZ
authors: Li
authors: Bernhard
authors: B
authors: Hauer
authors: Bettina
authors: B
authors: Rosche
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D019149:Bioreactors / Q000382:microbiology; D019855:Ethylene Glycol / Q000378:metabolism; D006016:Glycolates / Q000378:metabolism*; D011549:Pseudomonas / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D013997:Time Factors
chemical_list: D006016:Glycolates; C031149:glycolic acid; D019855:Ethylene Glycol