Isolation and screening of microalgal species, native to Zimbabwe, with potential use in biodiesel production

Abstract

Microalgae are increasingly being preferred as sustainable biomass feedstock for biofuels production due to their high growth rate and lipid yield. However, optimal production requires the use of economical native microalgal species which are well adapted to local climatic and ecological conditions. Therefore, this study's main objective was to isolate and select local microalgal species for prospective biofuels production. Serial dilution and streak plate techniques were used to isolate four species: Chlorella, Scenedesmus, Oscillatoria and Microcystis from Manyame River, Zimbabwe. The isolates were evaluated for their biomass and lipid productivity under artificial lighting (8:16 h light/dark cycle) and a temperature of 25 ± 3°C. Lipid quantification was done gravimetrically, using hexane as an extraction solvent. Each isolate's performance was compared against that of an imported Chlorella vulgaris strain. Amongst the isolates, Chlorella sp. exhibited a highly competitive growth rate of 0.26 d −1 and lipid yield of 37.16% dry cell weight. In comparison, the imported C. vulgaris had a growth rate of 0.226 d −1 and lipid yield of 35.74% dry cell weight. Although findings suggest that the native Chlorella sp. is the ideal candidate, growth enhancement and genetic engineering techniques may be used to further improve its biomass and lipid yield.

Elimination of Vibrio Cholerae from Raw Sewage Using Chlorella Vulgaris: A Case of Chegutu Waste Reticulation, Zimbabwe

“…In a study carried out by Taziki et al (2015), it was revealed that the microalgae were able to remove nitrates and nitrites from wastewater by assimilation. In Zimbabwe, Sero et al (2021) isolated and selected four microalgae native to Zimbabwe with potential use in biodiesel production. These were Chlorella spp, Oscillatoria spp.…”

Integration of Microalgae‐Based Wastewater Bioremediation–Biorefinery Process to Promote Circular Bioeconomy and Sustainability: A Review

“…showed good adaptability to new environment, highest growth rate, and high lipid productivities which are important selection criteria in biorefinery applications. [ 25 ]…”

“…showed good adaptability to new environment, highest growth rate, and high lipid productivities which are important selection criteria in biorefinery applications. [25] www.clean-journal.com Chlorella vulgaris and Dictyosphaerium sp. were screened on process water from pulp and paper mill as microalgal cultivation medium for biorefinery applications and biomass/lipid production.…”

Integration of Algal Biofuels With Bioremediation Coupled Industrial Commodities Towards Cost-Effectiveness

“…It is often argued that indigenous strains have better fitness to grow in that local environment (Winckelmann et al, 2015;Mutanda et al, 2020). Sero and colleagues reported that the microalgal strains isolated from extreme urban wastewater environments have inherent biological traits to proliferate in stress and capable of producing high biomass yield using wastewater (Sero et al, 2021). Adaptive evolution, mutagenesis, genetic engineering, and systems biology approaches have been used now for microalgal strain improvement with desired traits (Arora and Philippidis, 2021;Kumar Singh et al, 2021;LaPanse et al, 2021).…”