Abstract:
The generation of food waste by the food processing industry poses significant
environmental and economic challenges globally. This study investigated the potential of
utilizing industrial food waste as a source of nutrients for cultivation of the microalga
Desmodesmus sp. to produce value-added biomass rich in alpha-linolenic acid. The
objectives of the study were to identify the type of food waste and dilution factor of food
waste hydrolysate to maximize biomass and alpha-linolenic acid yields, and assess the
efficacy of nutrient recovery. The current study is the first in reported literature to utilize
industrial food waste for synthesis of microalgae-based alpha-linolenic acid. First, a
screening experiment was performed for growth of Desmodesmus sp. in hydrolysates of
brewery waste (BrW), biscuit waste (BiW), and Thriposha waste (TW) with four dilution
factors; 25%, 50%, 75% and 100% (undiluted hydrolysate). Higher biomass yields were
achieved in all waste types compared to the control medium (modified Bold’s Basal
media; 3N-BBM), with the maximum yield obtained using 100% TW. Thereafter,
Desmodesmus sp. was cultured in photobioreactors using 100% TW, with a 3N-BBM
control. The biomass growth rate and specific growth rate achieved in 100% TW
hydrolysate were 0.503 g L d and 0.214 d respectively, which were significantly higher
than the control. Biomass analysis showed that a significantly higher lipid content was
present in the 100% TW-cultivated biomass, suggesting a higher alpha-linolenic acid
extraction potential. Nevertheless, further research on techno-economic feasibility
assessment and toxicology analysis is required prior to large-scale adoption of this
process.
