Microalgae and the Factors Involved in Successful Propagation for Mass Production

Journal of Sustainability Science and Management eISSN: 2672-7226 Volume 16 Number 3, April 2021: 21-42 © Penerbit UMT MICROALGAE AND THE FACTORS INVOLVED IN SUCCESSFUL PROPAGATION FOR MASS PRODUCTION ALIFFIKRI RAMLEE3, NADIAH W. RASDI*1,2, MOHD EFFENDY ABD WAHID1 AND MALINNA JUSOH3 1Faculty of Fisheries and Food Sciences, 2Institute of Tropical Biodiversity and Sustainable Development, 3Faculty of Science and Marine Environment Universiti Malaysia Terengganu, 21300 Kuala Nerus,Terengganu Malaysia. *Corresponding author: [email protected] Submitted final draft: 14 Jun 2020 Accepted: 1 July 2020 http://doi.org/10.46754/jssm.2021.04.003 Abstract: Recently, microalgae have been regarded as useful organisms worldwide due to their potential for extensive application in renewable energy, aquaculture, biofuel and pharmaceuticals. Different species of microalgae have drawn significant interest because of their biological and chemical composition, which could potentially be useful in developing new applications in the aquaculture, biofuel and pharmaceutical industries. Furthermore, various culture techniques have been developed based on the species and environmental condition to ensure its mass production. Although microalgae are feasible sources for a successful biological product, limitations and challenges remain, which need to be solved with the innovation of new alternative technology in culturing and producing successful mass cultures. In this review, several current microalgae species production methods will be discussed based on their applications, and biological and chemical compositions, which are influenced by their growth parameters. Keywords: Microalgae, aquaculture, biological, chemical composition, growth parameter. Introduction galbana possess the potential for large-scale Microalgae are defined as microscopic single cultivation despite the insufficient information cells, which may be prokaryotic, such as to run commercial trials (Xu et al., 2009). cyanobacteria (chloroxybacteria), or eukaryotic. A high amount of microalgae biomass is They are similar to green algae (Chlorophyta). required to be on a par with the feedstock for Known as a class of photosynthetic organisms, sustainable production. According to Cheng et microalgae are typically found in freshwater al. (2019), the growth and biomass production aquatic and marine habitats, including rivers, of microalgae is significantly dependent on lakes, wastewater, oceans and estuaries. The cultivation conditions and concentration of growth of algae is possible in various conditions, microalgae, which can be manipulated based temperature levels, salinities, pH values and on their optimum culture parameter. light intensities. Alga can grow on its own or Moreover, the concentration of microalgae symbiotically with other aquatic organisms in a solution is an important element which (Barsanti et al., 2008). quantifies the productivity for biomass Some microalgae have high carbon production. Meanwhile, cell density is generally compound content, which may be utilized for defined as the concentration of microalgae in new organic-based products, including biofuels, a medium in terms of the number or mass of health supplements, pharmaceuticals, and cells per unit of volume, which is essential in cosmetics (Das et al., 2011). Furthermore, large- determining microalgae growth (Pahija et al., scale microalgae cultivation can contribute 2019). Therefore, the attraction of microalgae to the development of a sustainable industry as a sustainable and renewable bio-product has for biomass production and the development encouraged a new focus on biomass cultivation. of cost-effective high-value products. Many Improvements in growth, culture techniques and species of microalgae, such as Chlorella genetic engineering can be utilized to enhance vulgaris, Tetraselmis suecica and Isochrysis their potential as a future source of bio-products. Aliffikri Ramlee et al. 22 Microalgae as a Bioproduct fully adapt to environmental changes like pH, Different green algae species have been utilized temperature, light, carbon dioxide concentration, as food for decades (Jensen et al., 2001). The salinity and nutrients (Molina et al., 2003). cultivation of microalgae started when it was To achieve the highest microalgae realized there could be a lack of sources for productivity in a cost-effective manner, the protein-rich foods for a rapidly growing world selection of cultivation method is crucial. population (Borowitzka et al., 1988). Based Environmental factors play an important role in on previous research, the first large-scale controlling the growth phases of microalgae, but culture microalgae were the Chlorella species, they can be cultured through different methods which were reported to be used for commercial under various conditions. (Campbell et al., purposes in Japan in the 1960s (Iwamoto, 2004). 2011). Environmental source of nutrients and Over the last few decades, algae culturing has light are needed to convert the absorbed water expanded to new products, such as food and and CO2 into biomass through photosynthesis feed, biofuels, and biopharmaceuticals, along (Ozkurt, 2009), leading to the creation of with the use of natural products in algal extracts various products including cell components or in cosmetics and medicines (Luiten et al., 2003). storage materials, and vary from 20% to 50% Microalgae produce a wide range of other of total biomass (Chisti, 2007). Nitrogen and commercially valuable products, including phosphorus are the major nutrients required by essential vitamins for people and animals, and the algae. Nitrogen is a basic component for aquaculture purposes (Cuellar et al., 2011). In the development of proteins and nucleic acids, addition, microalgae contain important types of while phosphate is a vital component of DNA medicinally essential polysaccharide pigments, and RNA, which are essential macromolecules such as chlorophyll, β-carotene and other for all living cells. (Juneja et al., 2013). carotenoids, phycobiliproteins and astaxanthin Algae growth also requires macronutrients, (Guil et al., 2004). Previous work from Liang including Na, Mg, Ca, and K; micronutrients, et al. (2004) found that microalgae had been including Mo, Mn, B, Co, Fe, and Zn; and other used as nutrients, colouring agents and additives trace elements. Additionally, wastewater from in a variety of food products. Microalgae can, aquaculture and agriculture is a good source of therefore, be a promising source of bioproducts nutrients for microalgae cultivation. Although that can be applied to new production through different species of microalgae will go through mass cultivation. Microalgae must be modified different growth phases based on their needs and enhanced in order to produce a new type of for growth media in biomass production, the algae-based product that can be used as a food primary requirements are the same for almost for both humans and animals. all species (Campbell et al., 2011). Current Algae Production Algae Culturing Despite the wide range of potential applications Generally, the growth of microalgae may of microalgae for aquaculture and other useful be separated into four phases – lag, log or products, the production of microalgae has not exponential phase, stationary phase, and finally been fully commercialised due to several issues, death (Moazami et al., 2012). The initial lag including failure to overcome physiological phase is when the microalgae adapts to their stresses, nutrient deficiencies, high cost of mass surroundings, including the medium, pH, production and failure to identify the suitable temperature, and lighting. Subsequently, the conditions mass microalgae cultivation (Mallick microalgae begin to undergo active cell division, et al., 2016). Furthermore, some microalgae which is followed by an exponential increase either do not produce important metabolites or in the biomass of the culture (Chisti, 2007). produce them in small amounts under normal Following that, the stationary phase takes place, conditions. Some microalgae also do not Journal of Sustainability Science and Management Volume 16 Number 3, April 2021: 21-42 MICROALGAE AND THE FACTORS INVOLVED IN SUCCESSFUL PROPAGATION 23 which halts the increase in the biomass due to the of microalgae is influenced by light radiance equal rate of the cell division and death (Jusoh et and intensity, which affect the biochemical al., 2020). This phase mainly occurs as a result composition of microalgae and biomass yield of the depletion of nutrients in the medium (Paes (Krzemińska et al., 2014). Growth rate and et al., 2016). Consequently, the microalgae death biomass productivity are predicted as the rate would be higher compared to the rate of the function of light in the microalgae culture cell division. Microalgae can be cultured through system (Huesemann et al., 2013). Furthermore, different methods under various conditions and algae species vary in terms of light requirements the most important parameters in algae culturing for optimum growth and biomass production, is the type of growth system (Khan et al., 2018), and the rapid growth of microalgae would which should be designed according to the not take place under extremely low and high species and the purpose of culture. light intensities (Mata et al., 2010). Therefore, On a large scale, although algae can be optimal light intensity needs to be observed in each species of alga to maximise CO absorption cultured in low-cost open ponds, which are 2 ideal

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