Extractive fermentation for process integration and amplified pullulan production by A. pullulans in aqueous two phase systems
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Date
2019
Journal Title
Journal ISSN
Volume Title
Publisher
Scientific Reports
Abstract
Extractive fermentation technique or in situ product recovery process is a novel technique to segregate
the desired product simultaneously in a fermentation process. For economic and high yield production
of pullulan, Extractive fermentation process was applied fermentation process of A. pullulans. Aqueous
Two Phase system (ATPS) systems were designed with various molecular mass of PEG (400, 600, 4000
and 6000) and dextran or mono/bi-sodium phosphate salts. Systems with short Tie Line length (TLL)
6.7 and 7.5% w/w for PEG-Salt and PEG-dextran respectively were chosen. Volume ratio for all the
systems was kept constant at 1.0 and pH 7.0 for PEG-dextran and PEG-NaH2PO4 was maintained,
whereas pH 9.0 was kept for PEG-Na2HPO4. A. pullulans, was found to be viable with PEG-NaH2PO4 and
PEG-dextran systems. The biomass partitioned in the PEG rich top phase and the exopolysaccharide
pullulan shown affinity towards the bottom phase. A maximum yield (36.47 g/L) was found with PEG
4000-Dextran 500 system of extractive fermentation process. The proposed process aptly integrates
upstream and downstream process for continuous production and recovery of pullulan from the
biomass, thus reducing the time quotient of the whole process