Nanofiltration-based purification process for whole-cell transformed prebiotic galactooligosaccharides.

Area of Science:

• Biotechnology
• Food Science
• Separation Science

Background:

• Galactooligosaccharides (GOS) are valuable prebiotics.
• Current methods for GOS enrichment face challenges with purity and yield.
• Kluyveromyces marxianus 3551 is a microbial source for GOS synthesis.

Purpose of the Study:

• To investigate the enrichment of galactooligosaccharides (GOS) synthesized by Kluyveromyces marxianus 3551.
• To optimize GOS enrichment using nanofiltration technology.
• To evaluate the prebiotic potential of the enriched GOS.

Main Methods:

• Synthesis of GOS using whole cells of Kluyveromyces marxianus 3551 in a bioreactor.
• Fractionation of the synthesized sugar mixture using three different spiral wound nanofiltration membranes (polysulfone, cellulose acetate, polyethersulfone).
• Optimization of nanofiltration conditions (temperature, transmembrane pressure) using the best-performing membrane (polyethersulfone, 400-1000 Da cut-off).
• Analysis of sugar concentrations via high-performance liquid chromatography (HPLC).
• Microbial growth assays to assess prebiotic effectiveness.

Main Results:

• The polyethersulfone membrane (NFPES-03) demonstrated superior performance in fractionating the GOS mixture.
• Optimal GOS enrichment was achieved at 50 °C and 15 bar transmembrane pressure, maximizing trisaccharide and disaccharide/monosaccharide rejection.
• The integrated process achieved an 88.8% recovery of GOS.
• Nano-filtered GOS supported the growth of various microbes, confirming its prebiotic properties.

Conclusions:

• Nanofiltration, particularly with a polyethersulfone membrane, is an effective method for enriching galactooligosaccharides (GOS).
• Optimized conditions enhance GOS purity and recovery.
• The enriched GOS serves as a potent prebiotic source, validated by microbial growth studies.