Harnessing the Carbon Utilization Potential of Microalgae Cultivation for Sustainable Biofuel Production
Authors: Bahrim R. Z. Kamarul , Wazir N. Ahmad , Khairulanwar M. K. , Jalil M. M. , Yahya L. , Husein N. , Yahya M. A. , Onn M. S. , Bakri F. A. M , Abidin Q.H. Zainol , Harom Z. , Chan W. , Nor M. G. M , Ramli A. Sawal , Hamid P. Abdul , Yee H. Vai 
Published: November 2024

Abstract
This research explores the improvement of microalgae cultivation in Carbon Capture, Utilization, and Storage (CCUS) by leveraging their ability to convert CO2 and water into carbohydrates and lipids through photosynthesis. Lipids, a type of organic compound stored in microalgae, are critical for biodiesel production. This study aims to enhance CO2 utilization efficiency and biofuel production through optimized nutrient formulations and enhanced cultivation processes in open tanks designed for microalgae cultivation. Research involved cultivating microalgae in specialized tanks designed to maximize CO2 utilization. The comprehensive cultivation strategy integrated CO2 carbonator technology with eco-friendly nutrient formulations and involved precise regulation of various parameters, including light exposure, nutrient delivery strategy, air and CO2 circulation design. Systematic sampling, analysis, and carbon balance studies were conducted to assess biomass productivity and CO2 utilization efficiency. The suitability of the biomass for biofuel production was evaluated through lipid extraction and transesterification, where lipids react with alcohol in the presence of a catalyst to form biodiesel and glycerol. The specifically developed nutrient formulation facilitated a 127% increase in microalgae growth and a 37% uplift in lipid productivity compared to standard cultivation system without the CO2. The improved CO2 delivery system contributed to a calculated CO2 saving of more than 30% compared to traditional CO2 aeration methods with less than 5% CO2 loss to atmosphere, underlining the efficiency of the integrated approach in carbon capture and biomass generation. The combination of improved nutrient, cultivation strategy, and CO2 supplementation enhanced growth by more than 100% during the cultivation cycle. The biomass demonstrated high potential for biofuel production and other high-value applications, with approximately up to 40% of the lipids extracted from the dried algae biomass being converted to biodiesel. The residual solid waste was repurposed into bio-coal and other products, illustrating the versatility and sustainability of the process. The inclusion of microalgae open tank systems and enhanced CO2 utilization technology as part of nutrient development and cultivation strategy represents a significant advancement in microalgae cultivation for biofuel production and other products. This multi-layered approach combines advances in carbon capture-utilization and a range of biomass uses, highlighting the role of microalgae in progressing towards a sustainable and low-carbon future. By integrating microalgae cultivation with industrial CO2 emissions, the process not only reduces greenhouse gas emissions but also supports the production of renewable energy, contributing to net carbon zero goals.