Comparison of three analytical techniques for general characterisation of selected algae and cyanobacteria / Suhaina Nashath Mohamed Iqbal

Suhaina Nashath , Mohamed Iqbal (2020) Comparison of three analytical techniques for general characterisation of selected algae and cyanobacteria / Suhaina Nashath Mohamed Iqbal. Masters thesis, Universiti Malaya.

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Abstract

Algae and cyanobacteria maintain the oxygenation of earth, and are utilised as biofuels, biofertilizers and nutrition feed. The characterisation of algae and cyanobacteria through conventional methods require technical expertise, laborious sample preparation, and moderately expensive instruments and reagents. Hence, in this study, selected bioanalytical techniques with minimal sample preparation were incorporated, to simplify the characterisation of algae and cyanobacteria. The objectives of this research were to study the phylogenetic relationship of the selected algae and cyanobacteria via the 23S plastid ribosomal ribonucleic acid (rRNA) and 18S rRNA biomarkers; to validate the presence of the microcystin synthetase (mcy) gene cluster encoding the biosynthesis of microcystin in the selected cyanobacteria; to identify the organic compounds present in the selected algae and cyanobacteria via gas chromatography-mass spectrometry (GCMS); and to study the vibrational properties exhibited by the atom of the selected algae and cyanobacteria via Raman spectroscopy. Pure cultures of the selected algae and cyanobacteria were sourced from the culture collection centre. The deoxyribonucleic acid (DNA) of algae and cyanobacteria was extracted following the phenol-chloroform protocol, and subjected to the polymerase chain reaction (PCR) using the 23S plastid rRNA (p23SrV) biomarker. The taxonomic clade of brown algae (Chaetoceros calcitrans and Isochrysis galbana), green algae (Chlorella spp. and Tetraselmis spp.), and cyanobacteria (Microcystis aeruginosa and Nostoc spp.), were distinguished. This universal biomarker simplified the taxonomic classification of both algae (eukaryotic) and cyanobacteria (prokaryotic). Whereas, the 18S rRNA (18Sr) biomarker shows a further separation of C. calcitrans and I. galbana into two different clades, and green algae as a single clade. Furthermore, the mcy gene cluster was not expressed in both of the cyanobacteria species. In addition, in GC-MS analysis, the organic phase of algae and cyanobacteria was extracted via solvent extraction, prior to injecting in the Agilent 6890N Network GC system. The organic compounds, namely alkane, alkyne, alcohol, phenol, polycyclic hydrocarbon, aromatic ketone, and siloxane were eluted, based on its polarity and volatility properties. These compounds are bio-commercialised as biofuels, cosmetics and skincare, industrial polymers and lubricants, paint coatings, and paraffin waxes. Lastly, a thin film of air-dried algae and cyanobacteria were analysed in Renishaw In Via Raman Microscope. The Raman spectra produced corresponded with saffron and carotene photosynthetic pigments, at peaks 1010 cm-1, 1155 cm-1 and 1520 cm-1. These pigments can be extracted from algae and cyanobacteria, and bioengineered for industrial use. Briefly, this research serves as a baseline study for environmental monitoring and a quick approach to identify compounds, that are beneficial as biofuels and pharmaceutical products in the future. Freshwater algae and cyanobacteria could be a fundamental source for farmers to harvest, and convert waste materials to useful materials. Algae blooms which are potential biotoxins for fishes and prawns, can now be converted sustainably, in-line to convert waste to wealth strategy.

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