Palm oil mill effluent (POME) is a palm industrial waste by‐product that is readily available and possesses high quantities of the organic compounds that are necessary for microbial growth. This study investigated the potential of immobilized Aspergillus oryzae whole cells expressing Candida antartica lipase B (r‐CALB) when using a POME‐based medium as a low‐cost carbon source within biomass support particles. The dry cell weight, hydrolytic activity, and remaining protein were measured for a variety of POME (0–2% w/v) and carbon source concentrations (0–2% w/v) with an incubation time of 96 h. Using POME in the culture medium as a carbon source instead of glucose doubled the retention of cell weight from 1.16 ± 0.03 to 2.36 ± 0.02 g within the biomass support particles and improved the hydrolytic activity from 1.61 ± 0.02 to 2.23 ± 0.02 U mg−1 in whole‐cell lipase. This immobilized r‐CALB was used as a catalyst to esterify POME into biodiesel. This synthesis produced an ester content of 97.52 ± 0.21% w/w after 96 h. Immobilized r‐CALB was reusable for more than ten batches, and resulted in an ethyl ester content of more than 90% w/w even after 10 cycles. The present study demonstrated that POME could serve as a sustainable carbon source for industrial microbial culture with the additional incentive of being a treatment that is inexpensive and sustainable. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd

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The bottleneck for the production of biofuels from microalgae consists on costly harvesting processes and low lipid production, immobilization technology could play a part on making the production of biofuels more feasible. The aim of this study was to evaluate the effect of alginate immobilization on the growth and lipid productivity of the microalgae Chlorella sorokiniana, so far, the main focus of immobilization technology has been its use for wastewater treatment and nutrient removal from effluents. The microalgae Chlorella sorokiniana was cultured in both free and immobilized forms under optimal autotrophic growth conditions. Microalgae were immobilized in calcium alginate beads generated by mixing algal cells with a sodium alginate solution, followed by extrusion into a CaCl2 solution. The results obtained in this study showed that the growth of the microalgae immobilized in alginate beads, was enhanced and achieved a dry cell weight 1.4-fold higher than that of a free cell culture, a higher light transmittance was also achieved in the alginate immobilized culture, and the lipid productivity was increased from 54.21 ± 2.48 mg/L/d in the free cell culture to 82.22 ± 8.48 mg/L/d in the immobilized culture. These results demonstrate the effectiveness of immobilization technology for promoting growth and lipid productivity in the microalgae Chlorella sorokiniana.