Review

Biofilm reactors for industrial bioconversion processes: employing potential of enhanced reaction rates

Nasib Qureshi¹ , Bassam A Annous² , Thaddeus C Ezeji³ , Patrick Karcher³ and Ian S Maddox⁴

¹  National Center for Agricultural Utilization Research, United States Department of Agriculture**, Agricultural Research Service, Fermentation Biotechnology Unit, 1815 N University Street, Peoria, IL 61604, USA

²  Eastern Regional Research Center, United States Department of Agriculture, Agricultural Research Service, 600E Mermaid Lane, Wyndmoor, PA 19038, USA

³  University of Illinois, Biotechnology & Bioengineering Group, Department of Food Science & Human Nutrition, 1207 W Gregory Drive, Urbana, IL 61801, USA

⁴  Massey Univesity, Institute of Engineering & Technology, Palmerston North, New Zealand

author email corresponding author email

Microbial Cell Factories 2005, 4:24doi:10.1186/1475-2859-4-24

Published:	25 August 2005

Abstract

This article describes the use of biofilm reactors for the production of various chemicals by fermentation and wastewater treatment. Biofilm formation is a natural process where microbial cells attach to the support (adsorbent) or form flocs/aggregates (also called granules) without use of chemicals and form thick layers of cells known as "biofilms." As a result of biofilm formation, cell densities in the reactor increase and cell concentrations as high as 74 gL^-1 can be achieved. The reactor configurations can be as simple as a batch reactor, continuous stirred tank reactor (CSTR), packed bed reactor (PBR), fluidized bed reactor (FBR), airlift reactor (ALR), upflow anaerobic sludge blanket (UASB) reactor, or any other suitable configuration. In UASB granular biofilm particles are used. This article demonstrates that reactor productivities in these reactors have been superior to any other reactor types. This article describes production of ethanol, butanol, lactic acid, acetic acid/vinegar, succinic acid, and fumaric acid in addition to wastewater treatment in the biofilm reactors. As the title suggests, biofilm reactors have high potential to be employed in biotechnology/bioconversion industry for viable economic reasons. In this article, various reactor types have been compared for the above bioconversion processes.