LIQUEFACTION OF MICROALGAE WITH IRON CATALYST

Liquefaction of Spirulina, a high-protein microalga, afforded > 90 wt% of THF-soluble products and 60 wt% of hexane-soluble fractions, in th e temperature range 300-425 degrees C under hydrogen in various organi c solvents with highly dispersed catalysts. The oil yield increased fr om 52.3 to 66.9 wt% With Fe(CO)(5)-S catalyst at 350 degrees C for 60 min in tetralin under 5.0 MPa of hydrogen. Hydrogen activated by the d ispersed catalyst contributed to an increase in oil yield. Liquefactio n in water as solvent gave a higher oil yield of 783 wt% at 350 degree s C even under nitrogen. Liquefaction in toluene gave oil fractions of high carbon content and lower oxygen content, with a heating value of 32-33 MJ kg(-1). On the contrary, oil fractions obtained in water had a lower carbon content and higher oxygen content, with a lower heatin g value of 26 MJ kg(-1). The presence of moderate amount of water is c onsidered to be effective for the production of oil of high heating va lue in high yield. FT-i.r. spectroscopy and gel permeation chromatogra ph, showed that production of oil fractions proceeded via thermal deco mposition of polypeptides and hydrolysis by water produced during liqu efaction in organic solvents. (C) 1997 Elsevier Science Ltd.