Cultivation of Monoraphidium sp. on fruit peels to produce expedited lipids and carotenoids for the sustainable biorefinery

Microalgae-derived bioactive bioproducts are due to their potential application in pharmaceuticals and nutraceuticals. Nevertheless, the exorbitant cost of nutrients essential for microalgal cultivation is a significant obstacle to commercially feasible algal-mediated value-added compound manufacturing. Fruit waste like banana peel and sweet lime peels were used instead of traditional growing media in this investigation to cultivate Monoraphidium sp. These wastes are zero-value substances comprising essential nutrients and components to produce microalgae biomass. Response surface methodology (RSM) based on a central composite design (CCD) was used to analyze the optimization of fruit waste slurry with nitrogen content on biomass, lipids, and carotenoids production. When the Monoraphidium sp. was grown in 12.5 ml L−1 banana peel slurry (BPS) and 2.5 ml L−1sweet lime peel slurry (SLPS) with 1.5 g L−1 nitrogen (N), the most significant biomass yield of 1089 mg L−1, lipids of 14,362 RFU and carotenoids of 11.5 µg ml−1 were obtained. The TLC analysis revealed the presence of astaxanthin, regarded as a commercially established carotenoid. The results showed that these organic wastes could potentially serve as a sustainable, low-cost, and environmentally reliable alternative medium for the development of microalgae with boosted value-added compounds. © The Author(s) under exclusive licence to Society for Plant Research 2023.