In this paper, the viability of microalgae as a viable replacement feedstock for compression ignition engines is investigated. The characteristics of diesel fuel alternatives, including microalgae (MAME100), kapok oil (KA100), and soybean (SME100), as well as their blends with diesel, were studied. The results were used to compare the engine performance and emissions of D100, MAME100, MAME20, KA100, KA20D80, SME100, and SME20D80. The findings demonstrate that the addition of MAME20, KA20D80, and SME20D80 have been employed to assess engine output and emission. At 200 bar, the brake thermal efficiency (BTE) decreases by 2.0 % for MAME20D80, 1.5 % for KA20D80, and 2.0 % for SME20D80 as compared to D100. Specific fuel consumption (SFC) was shown to rise as KA20D80 levels rose by 3.8 %. The use of MAME20D80 and SME20D80 resulted in reductions of NO_x emissions of 10.0 % and 14.2 % as well as soot emissions of 10 % and 4.0 % as compared to D100. However, employing SME20D80, the blends produce greater carbon dioxide (CO₂) emissions of 11.4 %. In conclusion, a diesel engine can employ MAME20D80 and KA20D80.