| Abstract |
Aerobic granular sludge (AGS) provides the opportunity to recover resources such as phosphorus, alginate-like exopolysaccharides, polyhydroxyalkanoates, tryptophan, etc. Recently, xanthan, a versatile biopolymer with applications in the food, oil, geotechnical, and biomedical industries, has been identified in the aerobic granule matrix. The production of xanthan from waste is encouraged because conventional processes for its production are costly and require specialized laboratories. This paper presents an overview of xanthan recovery potential from AGS systems. Xanthan yields of 20.92 g/L and 30.64 g/L have been reported for blended wastewaters from different stages of white and rose wine production processes, respectively. Additionally, xanthan yield in the range of 4.28-15.56 g/L have been obtained from confectionary and brewery wastewaters. Currently, there is lack of information in the scientific literature on the factors that govern xanthan biosynthesis in AGS systems. Factors such as substrate type, carbon-to-nitrogen ratio, feeding strategy, hydrodynamic shear force, organic loading rate, hydraulic retention time, solids retention time, and feast/famine period require optimization for simultaneous efficient wastewater treatment and high xanthan biosynthesis. Moreover, quorum sensing and quorum quenching approaches require exploration for xanthan biosynthesis. Further research is also needed on the development of xanthan extraction and purification protocols from aerobic granules. |
