Malaysian Journal of Chemical Engineering & Technology

A mini-review on biosurfactants from natural-based resources: Sources, production, and application in oil industries

Tue, 30 Apr 2024 00:00:00 +0200

Increasing energy demand and depletion of producing wells around the globe necessitate oil industries to seek alternative mechanisms to increase oil production. Among various chemical enhanced oil recovery (CEOR) unveiled today, surfactants have become indispensable chemical agents in oil industries because of their wide applications in both onshore and offshore operational activities. Unfortunately, considerable numbers of these surfactants are synthetic causing treatment and disposal of effluents uneconomical to oil industries. This arises due to strong legislation laws enforced by governing bodies to ensure cleaner and safer environments. Consequently, the search for biodegradable surfactants from natural-based resources has revolved around the oil industries aimed at reducing the impacts of synthetic products both environmentally and economically. Plants are widely recognised as natural resources to obtain biosurfactants from their naturally producing saponins. In addition, other chemical compounds derived directly from plant parts are converted to biosurfactants commonly referred to as green biosurfactants. However, researchers have expressed reservations about sustainable biosurfactant production from plants due to limited access to plant resources. The present review discusses the types, properties, sources, synthesis, and applications of biosurfactants in EOR. Furthermore, the paper presents prospects of biosurfactants in EOR and proposes a sustainable production mechanism.

Simulation of microbial growth based on Euler’s method

Siti Humaira Mohd Jasni, Zaihar Yaacob, Zainatul `'Asyiqin Samsu — Tue, 30 Apr 2024 00:00:00 +0200

Microorganisms such as bacteria, fungi and yeast produce valuable metabolites when they are grown in suitable culture conditions. The cultivation condition affects the cell growth, metabolism, and product production in a sophisticated and nonlinear way. Therefore, in this research, the growth of Lactococcus lactis NZ9000 in response to the growth conditions was simulated using different growth models. The objective was to simulate the effect of temperature, agitation speed, carbon and nitrogen sources, on the cell growth using the exponential model, logistic and Monod equations. All equations were solved according to the Euler’s method using MATLAB R2021a for simulation. The experimental data used for the simulation were from literature. The accuracy of the model was expressed as percentage relative error between the maximum value of experimental and simulated data. Simulation results shows that the optimum conditions for cell growth was achieved at temperature 27°C, agitation speed of 100 rpm with glucose and peptone as the carbon and nitrogen sources respectively equation. The maximum cell concentration by logistic equation gives the lowest percentage error of 6.40% and 0.33% for the effect of temperature and agitation respectively. While Monod equation give the closest accuracy of 1.84% and 7.11% for carbon and nitrogen sources respectively. Thus, it was shown that the complexity of the microorganism growth was able to be simulated using suitable model such as logistic equation with the lowest relative error.

Exploring the prospects and challenges of underground hydrogen storage for a sustainable energy future

Tue, 30 Apr 2024 00:00:00 +0200

Compared to fossil fuel-based energy sources, renewable energy sources are gaining momentum worldwide due to climate control agreements. The Hydrogen Energy Roadmap proposes to generate hydrogen using renewable energy sources such as hydro, biomass, and solar. However, renewable energy source like hydrogen often has an unstable flow of energy supply, which can lead to temporary underproduction of the required supply. Underground storage options like depleted gas or oil reservoirs, aquifers, and salt caverns are used to address this issue. These underground gas storage alternatives have been used for various applications, including hydrogen storage. Underground hydrogen storage is possible in two geological sites: porous media and cave storage. Salt caverns are suitable for seasonal hydrogen storage at high pressures, while aquifers have the potential for hydrogen storage due to their widespread distribution. However, it is crucial to note that adequate reservoir properties and an impermeable layer are necessary for hydrogen storage in underground structures to prevent gas migration. Microbial and geochemical activities, often overlooked but crucial in hydrogen storage, can pose challenges due to their existence.