Efficient in-situ separation design for long-term sophorolipids fermentation with high productivity. (10th February 2020)

• Record Type: Journal Article
• Authors: Wang, Huaimin; Kaur, Guneet; To, Ming Ho; Roelants, Sophie L.K.W.; Patria, Raffel Dharma; Soetaert, Wim; Lin, Carol Sze Ki
• Is Part Of: Journal of cleaner production. Volume 246(2020)
• Publication Date: 2020-02-10
• Subjects: Food waste -- Fractionation -- High volumetric productivity -- Lactonic sophorolipids -- Separation efficiency; SLs Sophorolipids -- FWH Food Waste Hydrolysate -- RLH Restaurant Leftover Hydrolysate -- BWH Bakery Waste Hydrolysate -- PDA Potato Dextrose Agar -- HPLC High-Performance Liquid Chromatography -- HPLC-ELSD HPLC-Evaporative Light Scattering Detector -- FAN Free Amino Nitrogen -- CDW Cell Dry Weight -- OD Optical Density; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2019.118995
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Until now, the production of microbial biosurfactants has been limited to the use of first-generation (food) substrates. Moreover, the results on sophorolipids yield and productivity reported by state-of-the-art fed-batch processes for sophorolipids production remain unsatisfactory and lead to a significantly high cost per kg of the product. With an aim to address these problems, this study demonstrates a long-term and high-efficiency sophorolipids production method using a semi-continuous integrated production-separation system which utilizes food waste as a substrate. An average volumetric productivity of 2.43 g L −1 h −1 and the overall sophorolipids yield on the substrate (i.e. the combination of glucose and oleic acid as carbon source) of 0.73 g g −1 was achieved within 240 h by fed-batch and separation fermentation. Moreover, the potential of sustaining high production efficiency during long-term fermentation times (480 h) was investigated. No reduction in process efficiency was observed, i.e. average volumetric productivity and an overall sophorolipids yield of 2.39 g L −1 h −1 and 0.73 g g −1 were obtained, respectively. Notably, a very high biomass concentration of 117.2 g L −1 was observed in fed-batch fermentation and separation, which is the highest cell density ever reported for Starmerella bombicola . The separation efficiency was also calculated to evaluate the in-situ separation performance of the developed process quantitatively. In 480-h fermentation, the average separation efficiency of 74.3% and overall separation efficiency of 93.0% was achieved after six separation cycles, suggesting that both separation design and process control were successful in laboratory-scale fermentation. These findings demonstrate the potential of the developed sophorolipids fermentation-separation system for application at industrial scale. Graphical abstract: Image 1 Highlights: Food waste was used for sophorolipids (SL) fermentation. Combination of fed-batch with an in-situ separation strategy was developed. An average productivity of 2.4 g L −1 h −1 was obtained in 480 h fermentation. A yield of 0.73 g g −1 of carbon added was achieved. A cell density of 117.2 g L −1 and separation efficiency of 93.0% were achieved.