The indiscriminate discharge of Cassava mill effluent pose serious environmental and public health
implications. This work was aimed at assessing the biodegradation potentials of indigenous microbial isolates from
cassava mill effluent using screening and shake flask degradation tests. The mean heterotrophic bacterial and fungal
counts were 3.4±0.26 x 10
6cfu/ml and 1.1±0.20 x 10
6cfu/ml respectively. The microorganisms isolated, characterized
and identified include the genus
Pseudomonas
(15.48%),
Bacillus
(12.41%),
Acetobacter
and
Rhizopus
(10.88%),
Corynebacterium
(9.33%),
Lactobacillus
,
Micrococcus
and
Aspergillus
(7.79%),
Staphylococcus
and
Penicillium
(6.25%) and
Saccharomyces
species (4.62%). The pH (5.39 ± 0.14), electrical conductivity (2506.90 ± 45.35), sulphate
(210.87 ± 5.31), nitrate (365.28 ± 3.61), phosphate (107.70 ± 2.10), cyanide (19.93 ± 0.25), chemical oxygen demand
(1728.33 ± 19.66), biological oxygen demand (1141.51 ± 12.69), iron (206.43±2.05), zinc (54.56 ± 0.62), manganese
(19.96 ± 0.35), copper (10.67 ± 0.10) and nickel (3.28 ± 0.46) in mg/l were above the Federal Environmental Protection
Agency standard for effluent discharge.
Bacillus,
Pseudomonas,
Aspergillus and
Penicillium species which had the
highest turbidity were used for bioremediation studies. The consortium of microorganisms demonstrated the highest
efficacy. Bioremediation of cassava mill effluent by these microorganisms was manifested in the reduction of biological
oxygen demand (consortium of
Pseudomonas and
Bacillus species 97.42%), (
Aspergillus and
Penicillium species
75.32%) and chemical oxygen demand (
Pseudomonas and
Bacillus species 37.63%), (
Aspergillus and
Penicillium
species 44.97%). The study has shown that microbial isolates have the potentials of reducing pollution effect thereby
enhancing management of cassava mill effluent before eventual discharge into the environment.
