Cross-Flow Microfiltration of Glycerol Fermentation Broths with Citrobacter freundii.

Wirginia Tomczak,Marek Gryta

doi:10.3390/membranes10040067

Abstract

This paper reports the study of the cross-flow microfiltration (MF) of glycerol fermentation broths with Citrobacter freundii bacteria. A single channel tubular ceramic membrane with a nominal pore size of 0.14 µm was used. It has been demonstrated that the MF ceramic membrane has been successfully applied to bacteria cell removal and to effectively eliminate colloidal particles from glycerol fermentation broths. However, due to fouling, the significant reduction of the MF performance has been demonstrated. In order to investigate the impact of transmembrane pressure (TMP) and feed flow rate (Q) on MF performance, 24 experiments have been performed. The highest steady state permeate flux (138.97 dm3/m2h) was achieved for 0.12 MPa and 1000 dm3/h. Fouling analysis has been studied based on the resistance-in series model. It has been found that the percentage of irreversible fouling resistance during the MF increases with increasing TMP and Q. The permeate flux regeneration has been achieved by membrane cleaning with 3 wt % NaOH and 3 wt % H3PO4 at 45 °C. The results of this study are expected to be useful in industrially employing the MF process as the first step of glycerol fermentation broth purification.

Highlights

Microfiltration (MF) represents an alternative to conventional filtration processes and recently it is the mainstream separation technique used to treat suspensions
It indicates that microfiltration process is becoming increasingly attractive in the biotechnology industry in order to obtain a clarified filtrate from various bacterial products such as skim milk [1,2,3,4,5,6], skimmed colostrum [7], gum arabic suspension [8], cell suspension [9,10,11,12], fermentation soy sauce [13,14], and fermentation broths [15,16,17,18,19,20,21,22,23,24,25]
It should be mentioned that since compounds dissolved in fermentation broths were not rejected by the MF membrane, the solute concentrations in the permeate were the same as to those determined in the feed

Summary

Introduction

Microfiltration (MF) represents an alternative to conventional filtration processes and recently it is the mainstream separation technique used to treat suspensions. It indicates that microfiltration process is becoming increasingly attractive in the biotechnology industry in order to obtain a clarified filtrate from various bacterial products such as skim milk [1,2,3,4,5,6], skimmed colostrum [7], gum arabic suspension [8], cell suspension [9,10,11,12], fermentation soy sauce [13,14], and fermentation broths [15,16,17,18,19,20,21,22,23,24,25]. It has to be pointed out that with regard to complex media such as fermentation broths, microfiltration is proposed as a pre-treatment stage for the final separation by nanofiltration (NF) or reverse osmosis (RO) processes with spiral-wound modules [26]

Methods

Results

Conclusion