3 research outputs found
Bioremediation of heavy metal polluted water using immobilized freshwater green microalga, botryococcus sp.
Get PDFHeavy metal containing wastewater are regarded as highly toxic to the aquatic
environment and to life in general due to their bio-accumulating, cytotoxic,
mutagenic and carcinogenic effects on life. Bioremediation is the use of biological
materials (e.g. microalgae) in the removal of toxic compounds from the environment
such as the heavy metals which is considered more cost effective and
environmentally friendly when compared to the physical and chemical methods. The
present study was undertaken to check for the heavy metal bioremoval efficiency of
free and immobilized Botryococcus sp. Four heavy metals were studied and the free
cells efficiently reduced Chromium which is equivalent to 94%, followed by Copper
(45%), Arsenic (9%) and Cadmium (2%). For the immobilized biomass, the highest
(P<0.05) removal efficiency was recorded in the highest biomass concentration (i.e.
15 beads/ml) for Cadmium, Arsenic and Chromium at 76%, 68% and 67%. Whereas,
the highest (P<0.05) removal of copper was observed in the blank alginate beads at
84%. The positive control (free cells) recorded the highest (P<0.05) reduction for
biological oxygen demand (BOD) whereas, the 15 beads/ml gave the highest
(P<0.05) reduction for control gave the highest (P<0.05) reduction for the Chemical
oxygen demand (COD). In the LD50 experiment, immobilized biomass harvested
from the bioremoval study experiment were used on fishes for toxicity testing. A
total of 100% mortality was recorded in the positive control after 24 hours whereas,
3% mortality was observed in negative control and in the 10 beads/ml treatment after
72 hours. No mortality was found in any other treatment after a period of 96 hours.
The results obtained from this study suggests that, immobilized cells of
Botryococcus sp. is efficient in the bioremoval of heavy metals from contaminated
waters and also have great potential in the biotransformation of toxic compounds to
less-toxic forms
Growth of Freshwater Microalga, Botryococcus sp. in Heavy Metal Contaminated Industrial Wastewater
Get PDFThe aim of this study was to determine the growth and the bioremoval capacity of the green microalga, Botryococcus sp. grown in industrial wastewater contaminated with heavy metals. The freshwater green microalga, Botryococcus sp. was cultured in different concentrations of wastewater (25%, 50% and 100%) with an initial cell concentration of 1000 cells/ml for a period of 12 days. Bold basal medium and sterile distilled water were used as positive and negative control, respectively. The Botryococcus sp. grown in Bold’s basal medium showed the highest (P<0.05) average growth rate (7.8 × 106 cells/ml) after a period of 12 days, whereas, the lowest (P<0.05) growth was observed in 50% concentration of wastewater (4.8 × 104 cells/ml). Similar results were obtained for the specific growth rate (µ/day) with an average of 1.93µ/day and 1.22µ/day for the positive control and the 50% concentration respectively. Highest reduction of heavy metals was achieved for chromium which is equivalent to 94%, followed by copper (45%), arsenic (9%) and cadmium (2%). The results of this study suggest the potential of Botryococcus sp. as bioremediator of wastewater contaminated with heavy metals. 
Growth of Freshwater Microalga, Botryococcus sp. in Heavy Metal Contaminated Industrial Wastewater
Get PDFThe aim of this study was to determine the growth and the bioremoval capacity of the green microalga, Botryococcus sp. grown in industrial wastewater contaminated with heavy metals. The freshwater green microalga, Botryococcus sp. was cultured in different concentrations of wastewater (25%, 50% and 100%) with an initial cell concentration of 1000 cells/ml for a period of 12 days. Bold basal medium and sterile distilled water were used as positive and negative control, respectively. The Botryococcus sp. grown in Bold’s basal medium showed the highest (P<0.05) average growth rate (7.8 × 106 cells/ml) after a period of 12 days, whereas, the lowest (P<0.05) growth was observed in 50% concentration of wastewater (4.8 × 104 cells/ml). Similar results were obtained for the specific growth rate (µ/day) with an average of 1.93µ/day and 1.22µ/day for the positive control and the 50% concentration respectively. Highest reduction of heavy metals was achieved for chromium which is equivalent to 94%, followed by copper (45%), arsenic (9%) and cadmium (2%). The results of this study suggest the potential of Botryococcus sp. as bioremediator of wastewater contaminated with heavy metals. 
