Production of Hydroxy Fatty Acids and 5‑Hydroxy Methyl Furfural from Microalgal Biomass: An Integrated Biorefinery Perspective Involving Chemical and Enzymatic Conversion

A novel biorefinery process utilizing microalgal biomass has been developed, focusing on the enzymatic biotransformation of microalgal fatty acids in hydroxy fatty acids (HFAs) and the chemical conversion of the cellular debris to 5-hydroxymethyl furfural (5-HMF). First, the process was demonstrated using the dry biomass of the microalgal strains Chlorella sp. CW2, and Chlorella sp. Barcarello and Nannochloropsis gaditana obtained a C18:1 substrate reduction of approximately 68.7, 83.4, and 71.5% and a maximum 5-HMF yield of 28.6 ± 1.4, 35.2 ± 5.4, and 25.2 ± 1.5%, respectively. Further optimization of the process was performed on the wet biomass of the microalga Chlorella sp. CW2 by using intensified process operations, achieving the production of double-functionalized HFAs. The described process yields building blocks for the chemical industry starting from microalgal biomass, potentially sourced from the biological treatment of wastewaters. The enhanced sustainability and reduced operational costs provided by this innovative biorefinery approach represent significant advancements in the microalgal industry.