2 research outputs found
Investigation of the Effect of Initial Biomass on Nitrate and Phosphate Removal from Synthetic Wastewater by Selected Bacteria Isolates
Although nitrogen and phosphorus are important nutrients to the existence of living organisms, their presence in
excessive amounts in wastewater could have detrimental effects to humans and other living organisms. The
present investigation was aimed at ascertaining the effect of initial biomass concentration on the nutrient removal
efficiency of four bacterial species in synthetic wastewater under shaking flasks conditions. Four different initial
biomasses [2.91 x 108 cfu/mL, 5.82 x 108 cfu/mL, 8.73 x 108 cfu/mL and 1.16 x 109 cfu/mL (Klebsiella sp.); 6.31
x 108 cfu/mL, 1.26 x 109 cfu/mL, 1.89 x 109 cfu/mL and 2.52 x 109 cfu/mL (Pseudomonas sp.); 1.75 x 108
cfu/mL, 3.49 x 108 cfu/mL, 5.24 x 108 cfu/mL and 6.98 x 108 cfu/mL (Lysinibacillus sp.), and 7.1 x 108 cfu/mL,
1.42 x 109 cfu/mL, 2.13 x 109 cfu/mL and 2.84 x 109 cfu/mL (Staphylococcus sp.)] were used for the study. For
nutrient removal studies, the respective initial biomasses of the test isolates were inoculated into flasks
containing the wastewater media. Aliquot samples were taken at the beginning of the study and every 24 h for 96
h for the estimation of growth rate, pH, phosphate and nitrate concentrations in the wastewater, using standard
methods. The results revealed only slight phosphate decreases in the wastewater after the expiration of
incubation. All the test isolates showed significant nitrate removal ability except the Lysinibacillus sp. After 96 h
incubation 68.36 to 90.67 %, 91.80 to 95.29 %, 3.20 to 11.48 % and 86.77 to 94.33 % of nitrate was removed in
the presence of the Klebsiella sp., Pseudomonas sp., Lysinibacillus sp. and Staphylococcus sp., respectively. The
study was able to reveal the phosphate and nitrate removal ability of the isolates at the different initial biomasses
used for the investigation.
Keywords: Bacteria, wastewater, nutrient removal, phosphate, nitrat
Incidence of entomopathogenic Bacillus spp. in some plantations in Ibadan, Nigeria
Soil samples from some agricultural research plantations (IITA, CRIN, IAR&T, NIHORT and FRIN) in Ibadan metropolis, Nigeria were screened for the presence of entomopathogenic strains of Bacillus species. The loamy-sand and sandy-loam
soil types were typical soil texture of these locations with soil pH ranging between 4.9 and 6.1. The loamy-sand soil type recorded the highest number of Bacillus spp. and the history of pesticides applied on the sampling locations did not seem to affect the distribution of Bacillus thuringensis and other entomopathogenic Bacillus spp. in the different soils. Eighty-two strains of Bacillus spp. were isolated
with only seven of these being entomopathogenic. The seven strains of Bacillus spp. were toxic to Anopheles mosquito larvae exhibiting between 5% and 15% mortality within 72h