EVALUATION OF THE FLOCCULATION EFFICIENCY OF Chlorella vulgaris MEDIATED BY Moringa oleifera SEED UNDER DIFFERENT FORMS: FLOUR, SEED CAKE AND EXTRACTS OF FLOUR AND CAKE

Abstract

Flocculation as a pre-separation method can help make production of biodiesel from microalgae economically feasible. In a previous study, Moringa oleifera seed flour (1 g.L-1) was shown to be a very efficient flocculant for Chlorella vulgaris, a microalga with high potential for biodiesel production. In this study, several aspects of C vulgaris flocculation mediated by Moringa were investigated in order to optimize the separation of this biomass. Flocculation efficiency was the same with seeds from different origins and lots. The stationary growth stage was best for harvesting C vulgaris cells to carry out flocculation efficiently (93%). The use of flour extracts and cake extracts generated the best cost-benefit ratio (flocculation efficiency from 78 to 97% with a saving in mass of seed of 75%). The highest efficiency was reached with extracts prepared with seawater and NaCl solutions which have high salt concentration. Reasonable stability of the extract allows its use for up to two weeks, provided it is kept at low temperature (4 °C).

Harvesting Chlorella variabilis Biomass Using Moringa oleifera Seed-induced Sedimentation

“…The optical density decreased from 5.2 to 2.1 (about 60% decrease) when an extract from 5 g/l seed was added. Although, the percentage sedimentation obtained in the present experiment was lower than that of other workers [35,39] the extraction procedures used here and extraction time were different. The algal species were also not the same and the medium pH was not adjusted in the present experiment.…”

“…Recently, some researchers have reported the use M. oleifera seeds in various forms to harvest microalgae since it is cheap, easily available and non-toxic. Teixeira and Teixeira [35] used seed cake, seed flour and extract from cake and flour to flocculate Chlorella vulgaris. Hamid et al [36] compared the abilities of M. oleifera seed flour, protein powder and alum to flocculate Chlorella sp.…”

Water quality restoration by harvesting mixed culture microalgae using Moringa oleifera

“…and without oil extraction (MOWE) and reported that MOAE had flocculation efficiency of 93.77% at pH 7 with long settling time of 150 min at 5,000 mg/L dosage, whereas MOWE had flocculation efficiency of 70.56% at same pH, settling time 90 min, and 4,000 mg/L dosage. Teixeira and Teixeira (2017) evaluated the flocculation efficiency of Chlorella vulgaris harvested by M. oleifera seed under different forms: flour, seed cake, and extracts of flour and cake. The use of flour extracts and cake extracts had the best cost-benefit ratio with increased removal efficiency when the extract was made with saline and seawater (Teixeira & Teixeira, 2017).…”

“…Teixeira and Teixeira (2017) evaluated the flocculation efficiency of Chlorella vulgaris harvested by M. oleifera seed under different forms: flour, seed cake, and extracts of flour and cake. The use of flour extracts and cake extracts had the best cost-benefit ratio with increased removal efficiency when the extract was made with saline and seawater (Teixeira & Teixeira, 2017). Ali, Mustafa, and Saleem (2018) compared natural coagulants such as de-oiled jatropha curcas cake, M. oleifera, conocarpus erectus, and neem seeds with alum as a chemical coagulant.…”

“…In view of these advantages, M. oleifera seed extract can be an excellent alternative to chemical coagulants with potential applications in water treatment in developing countries (Ndabigengesere & Narasiah, 1998). The seeds from different origins and lots have almost the same efficiency (Teixeira & Teixeira, 2017). Abdul Hamid et al (2014) evaluated Chlorella sp.…”