In situ hollow fiber membrane facilitated CO2 delivery to a cyanobacterium for enhanced productivity

Abstract

Recently, cyanobacteria have been metabolically engineered to secrete valuable biofuel precursors eliminating the requirement to harvest and post-process algal biomass. However, development of new photobioreactors (PBRs) that can efficiently deliver light and address the mass transport challenges associated with maintaining high cyanobacteria productivity has been lagging. Hollow fiber membranes (HFMs) are a method for bubble-less gas exchange which has been shown to be effective at enhancing mass transfer. Previous applications of HFM technology to PBRs have been limited to exploring its ability to enhance CO 2 delivery to the bulk liquid volume. To investigate potential strategies for novel PBR design configurations, we examined the growth pattern of Synechococcus elongatus around individual HFMs to determine the optimal spacing and conditions for maximizing photosynthetic activity. We have shown that a single fiber enabling passive transport from/to the atmosphere can provide enough gas exchange to increase biomass accumulation by .2.5 times with respect to a non-fiber control. This increased growth was found to decay in the radial direction with the enhanced growth area spanning between 1.2 mm and 1.7 mm depending on the initial inoculation concentration.

Microalgae on display: a microfluidic pixel-based irradiance assay for photosynthetic growth

“…The maximum growth rate was 1.19 ± 0.02 day -1 , well within the range of 1-3 day -1 reported in literature. 8,42,43,[49][50][51] The most comparable conditions to our case were recently used by Kuan et al 49 who reported a growth rate of 1.25 day -1 for an irradiance of 120 µmol·m -2 s -1 at a temperature of 33 °C and an atmospheric CO2 concentration. Achieving higher growth rates was achieved in other works using elevated CO2 concentrations.…”

Cyanobacteria as an eco‐friendly resource for biofuel production: A critical review

“…This method with providing lower energy and cost seems to be beneficial for the commercial production of biofuel. Kalontarov et al designed a hollow fiber membrane (HFM) for CO 2 delivery in a photobioreactor. The cultivation of Synechococcus elongatus using HFM technology increased the cyanobacterial growth and biomass accumulation.…”

Porous Hollow Fiber Nickel Electrodes for Effective Supply and Reduction of Carbon Dioxide to Methane through Microbial Electrosynthesis

“…Hence, the development of a cathode architecture with a three‐phase interface (i.e., between CO 2 gas, cathodic biofilm, and electrolyte) is highly desirable. Bubble‐less gas exchange hollow fiber membranes (HFM) are effective for delivering gaseous substrate, and they have been used in a variety of applications from photo‐bioreactors, membrane‐supported biofilm reactors (MBfR) for water and wastewater treatment, tissue engineering, and development of artificial organs . In MBfR, gaseous substrate is delivered directly from the inside of hollow fibers to a biofilm attached on the outer wall of the HFM.…”