Mikroalga menunjukkan potensi yang besar dalam rawatan air sisa biologi serta pengeluaran biofuel. Ini adalah disebabkan oleh keupayaan mikroalga dalam memakan nutrien yang berlebihan dan pengeluaran lipid daripada biojisim. Walaupun banyak kemajuan dalam era ini, banyak cabaran menghalang pengkomersilan mikroalga dalam pengeluaran biofuel. Ini adalah disebabkan oleh teknologi dalam penuaian dan pemisahan mikroalga adalah mahal kerana mikroalga hidup dalam penyebaran. Dalam kajian ini, dua reaktor telah ditubuhkan untuk siasatan di mana reaktor 1 (R1) (reaktor kawalan) dan reaktor 2 (R2) (nitrogen kebuluran). Kesan nutrient yang tersedia terhadap profil pertumbuhan dan perkumuhan bahan polimer extrcellular (EPS) oleh mikroalga kedua-dua reaktor telah disiasat. Sampel dari kedua-dua reaktor telah dikumpulkan pada selang awalan untuk mixed liqour suspended solids (MLSS), mixed liquor volatile suspended solids (MLVSS), analisis nutrien dan analisis kandungan EPS. Dalam kajian ini, mikroalga dalam R1 dan R2 menunjukkan fasa lag, fasa eksponen dan fasa pegun. Walaupun, R2 dibiarkan dengan tempoh kebuluran, kepekatan maksimum mikroalga dan profil pertumbuhan menunjukkan tren yang sama seperti R1. EPS dalam kedua-dua reaktor meningkat dari masa ke masa. Walau bagaimanapun, penurunan kandungan EPS semasa kekurangan nitrogen dalam R2 dicatat. Ini mungkin dijelaskan oleh korelasi berkadar terus perkumuhan EPS terhadap nutrient yang tersedia. Komposisi EPS seperti Protein dan Karbohidrat dianalisis untuk pemahaman lanjut dan korelasi. Protein didapati sebagai komponen utama EPS dalam kedua-dua reaktor. kandungan karbohidrat EPS didapati rendah dalam kedua-dua reaktor dan ia mungkin digunakan oleh mikroalga sebagai sumber tenaga.
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Microalgae shows a great potential in biological wastewater treatment as well as biofuel production. This is due to microalgae’s capability in consuming excess nutrients and production of lipid from the biomass. Despite many advancements in this era, many challenges restrain the commercialisation of microalgae for biofuel production. This is due to the technology in harvesting and separation of microalgae is costly. In this study, the effect of nutrient availability on the growth profile and extracellular polymeric substance (EPS) excretion by microalgae were investigated. Two reactors were set up for investigations in which Reactor 1 (R1) (control reactor) and Reactor 2 (R2) (nitrogen starved), samples from both reactors were collected at prefixed interval for mixed liquor suspended solid (MLSS), mixed liquor volatile suspended solid (MLVSS), nutrient analysis and EPS content analysis. In this investigations, microalgae in R1 and R2 exhibit lag phase, exponential phase and stationary phase. Although, R2 were subjected with starvation period, the maximum concentration of its microalgae and the growth profile shows similar trend as R1. The EPS production in both reactors increases over time. However, the EPS content during nitrogen shortage in R2 was found decreases. This might be explained by the directly proportional correlations of EPS excretion to the nutrient availability. Composition of EPS such as protein and carbohydrate was analysed for further understanding and correlation. Protein was found as the major component of EPS in both reactors. Carbohydrate content of EPS was found low in both reactors and it might be consumed by microalgae as energy source.
Study on the effect of nutrient on microalgae growth profile and extracellular polymeric substance excretion / Siti Najeeha Sheikh Abdullah