Phycoremediation of Food Waste using Alginate-immobilized Chlorella vulgaris FSP-E Biosorbent and Reusing Treated Biomass for Biofertilizer Production

Abstract

Around 2.5 billion tonnes of food waste are generated globally every year, which is associated with many environmental issues (i.e. greenhouse gas emissions), economic issues, and ethical issues. Thus, a sustainable and innovative approach is implementing alginate-immobilized microalgae to remove contaminants from food waste. Sodium alginate is a gel matrix type used for microalgae encapsulation. This polysaccharide can form gel-like structures in the presence of multivalent cations such as Ca 2+ . In this research project, Chlorella vulgaris FSP-E is encapsulated with sodium alginate and implemented in food waste for phycoremediation. After food waste treatment, the microalgae biomass is reused as biofertilizers, and its performance in assisting plant growth and development is analyzed. After food waste treatment, it is found that the alginate-microalgae beads cause alterations in food waste media color and performed the highest COD removal of 95.7%. However, the beads had alterations on their appearance and some had decreased on bead stability, speculated due to microorganism contamination. The biomass is also discovered to experience a decrease in carbohydrate and lipid composition due to limited nutrient supply. Additionally, the implementation of the biomass as biofertilizer is considered to be insignificant (p > 0.05) for lettuce growth mainly due to improper planting techniques of the lettuce.