Biotreatment of discarded fruit juices and simultaneous lipid production using Leptolyngbya sp.

Abstract

AbstractBACKGROUNDFruit juices are an exceptional source of nutrients; however, due to their short shelf‐life and vulnerability to microbial degradation, large volumes of juice are regularly discarded worldwide. As a wastewater, discarded fruit juices (DFJ) possess high organic loads with significant amounts of nitrogen and phosphorus, making them a suitable substrate for microbial growth and to produce natural bioactive compounds.RESULTSDiscarded fruit juices (DFJ) were treated and simultaneously valorized (producing microbial lipids) using a microbial consortium dominated by the photosynthetic cyanobacterium Leptolyngbya sp. The effects of N:P and C:N ratios on growth and lipid production were examined, along with the ability of the consortium to biotreat DFJ in laboratory‐scale (LS) reactors. Using the optimum nutrient ratios (N:P 5:1, C:N 50.2:1), scaled‐up reactors (aquariums) were then tested under suspended and attached growth conditions. The biomass produced was further exploited for lipid production and the results revealed that Leptolyngbya sp. was able to produce up to 19% d.w. lipids and simultaneously efficiently treat DFJ. High dissolved‐chemical oxygen demand (d‐COD), total nitrogen, and PO43− removal rates (85.0% and 93.9%, 93.4% and 95.2%, 84.6% and 83.9%, respectively) were achieved in both the suspended and attached growth systems, along with high biomass productivities (316.3, 340.0 mg L−1 day−1, respectively).CONCLUSIONThe biological approach used in this study demonstrated that is possible to exploit DFJ and achieve satisfactory lipid contents (up to 19% d.w.) using a cyanobacterial‐based consortium. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).