Microalgae are promising sustainable energy sources for biodiesel production due to their rapid photosynthesis growth rate and capacity to be cultivated in wastewater, seawater, or freshwater. Moreover, microalgae could complete the entire growth cycle via photosynthesis reactions that convert light energy into renewable energy. The closed photobioreactor, PBR is resistant to infection from uninhabited algae species and allows frequent monitoring of various factors such as temperature, light intensity, and pH during the cultivation phase. Thus, this study focuses on continuous cultivation technology which produces higher biomass productivity with sustainable energy-saving operation as compared to batch culture. High productivity of microalgae biomass tends to accumulate higher concentrations of lipid and carbohydrates composition which is essential for the production of biofuels. The energy balance of numerous microalgae-based biofuels was discussed, and it was discovered that the net-energy ratio was greater than 1, indicating that the process is both commercially feasible and environmentally friendly. This study also summarizes the most recent discoveries on continuous cultivation constraints through photobioreactors, PBRs as well as potential challenges to tackle in scaling up the continuous sustainable culture mechanism. The research gaps, market opportunities, and future development directions of continuous photobioreactor systems are discussed to explore future development opportunities. A continuous photobioreactor, architecture is recommended for a pilot-scale trial, as a cost-benefit comparison would be beneficial in commercializing the framework.

Continuous cultivation of microalgae in photobioreactors as a source of renewable energy: Current status and future challenges

Sustainable biohydrogen production by Chlorella sp. microalgae: A review

This review presents the extractions, characterisations, applications and economic analyses of natural coagulant in separating pollutants and microalgae from water medium, known as microalgae harvesting. The promising future of microalgae as a next-generation energy source is reviewed and the significant drawbacks of conventional microalgae harvesting using alum are evaluated. The performances of natural coagulant in microalgae harvesting are studied and proven to exceed the alum. In addition, the details of each processing stage in the extraction of natural coagulant (plant, microbial and animal) are comprehensively discussed with justifications. This information could contribute to future exploration of novel natural coagulants by providing description of optimised extraction steps for a number of natural coagulants. Besides, the characterisations of natural coagulants have garnered a great deal of attention, and the strategies to enhance the flocculating activity based on their characteristics are discussed. Several important characterisations have been tabulated in this review such as physical aspects, including surface morphology and surface charges; chemical aspects, including molecular weight, functional group and elemental properties; and thermal stability parameters including thermogravimetry analysis and differential scanning calorimetry. Furthermore, various applications of natural coagulant in the industries other than microalgae harvesting are revealed. The cost analysis of natural coagulant application in mass harvesting of microalgae is allowed to evaluate its feasibility towards commercialisation in the industrial. Last, the potentially new natural coagulants, which are yet to be exploited and applied, are listed as the additional information for future study.

Insight on Extraction and Characterisation of Biopolymers as the Green Coagulants for Microalgae Harvesting

Multi-objective optimization of media components for improved algae biomass, fatty acid and starch biosynthesis from Scenedesmus sp. ASK22 using desirability function approach

Enhanced CO2 fixation and lipid production of Chlorella vulgaris through the carbonic anhydrase complex.

Recently, microalgae are common in both industrial and scientific cultivation. There are different fields of application for microalgae includes food, biofuels, fish feed and pharmaceutical products [1]. Recently, various applications were found for Chlorella vulgaris (C. vulgaris) such as a health food, fish feed and nutrition supplements for human consumption, as well as for lipid and biodiesel production. Algae produced its own food by autotrophic nutrition. The food produced is stored as carbohydrates (mainly as starch) and lipid [2,3].

https://medcraveonline.com/JAMB/JAMB-06-00143.pdf

KC Ho

Papers

Growth Medium Screening for Chlorella vulgaris Growth and Lipid Production