Nagaarasan A/l Ramesh, <br/><br/>
Kinetics studies and thermodynamics of oil extraction from immobilized microalgae cells of chlorella vulgaris / 
Nagaarasan A/l Ramesh 
 - xii, 78 pages :  illustrations (some color) ;  30 cm. +  1 CD-ROM. 
<br/><br/> Faculty of Chemical and Process Engineering Technology 
<br/><br/>Thesis (Master of Science) -- Universiti Malaysia Pahang - 2025 
<br/><br/>Includes bibliographical references 
<br/><br/> Microalgae have attracted considerable attention as a promising feedstock for biodiesel production owing to their rapid growth rate, high photosynthetic efficiency, and lower land-use requirements compared to conventional crops. However, commercial biodiesel production from microalgae remains limited due to insufficient understanding of efficient harvesting and oil extraction processes. To address these challenges, this research introduced a novel approach by investigating the oil extraction from immobilized Chlorella vulgaris cells using various chemical matrix combinations — namely sodium alginate (SA), sodium alginate/calcium alginate (SACA), sodium alginate/carboxymethylcellulose (SACMC), and a mixed matrix of sodium alginate/calcium alginate/carboxymethylcellulose (SACACMC). Immobilization was explored as an improved harvesting method due to its lower energy demand, simplified biomass recovery through filtration, enhanced cell viability, and economic feasibility compared to traditional harvesting techniques like centrifugation or flocculation. This study explores the kinetics and thermodynamics of oil extraction from Chlorella vulgaris, using immobilization as an alternative harvesting method. Experimental results demonstrated that microalgae biomass immobilized using the SA matrix alone yielded the highest oil extraction percentage (27.42%), significantly outperforming other matrices (SACA: 23.96%, SACMC: 23.86%, SACACMC: 23.42%). Kinetic analyses indicated that the SA matrix provided the highest reaction rate constant (2.79 × 10⁻³ min⁻¹), while thermodynamic analyses revealed favourable properties, including the lowest enthalpy (ΔH = 0.111 kJ/mol) and negative Gibbs energy (ΔG = -0.311 to -2.254 kJ/mol), signifying a spontaneous, irreversible, and thermodynamically feasible extraction process. Subsequent studies examined solvent effects on oil extraction from the SA-immobilized biomass using heptane, heptane/methanol, and heptane/ethanol. Extraction using heptane alone consistently showed the highest oil yield, greatest reaction rate constants, and thermodynamically favourable results. atty acid methyl ester (FAME) profiling via GC-MS analysis confirmed the superior quality of extracted oil from SA-immobilized cells using heptane, characterized by high concentrations of desirable biodiesel constituents: palmitic (55%), stearic (7%), oleic (24%), linoleic (4%), and linolenic (9%) acids. Thus, this study highlights the potential of microalgae immobilization coupled with optimized solvent extraction as an innovative, energy-efficient, and effective method for sustainable biodiesel production. 
<br/><br/><label>ISBN: </label>THE0010364 (Local) 
<br/><br/><label>Subjects--Corporate Names: </label><br/>Faculty of Chemical and Process Engineering Technology--Dissertations
<br/><br/><label>Subjects--Topical Terms: </label><br/>Universities and colleges--Dissertations<br/>Theses--Dissertations