Jatropha curcas is a multipurpose plant that has been suggested as a possible cure to
inflammation. It can be used as a source of animal feed, live fence, biodiesel and in traditional
medicine. Practitioners have used various extraction techniques to extract the active components
of the plant. This article compares the efficiency of three methods of drying technique for the
extraction of the total phenolic content from the plant. The freeze-drying method was the best
method compared to oven dry and air dry. The freeze-drying method dries J. curcas root sample
faster and preserve the total phenolic content better than the other methods.
Pollution in the environment is deteriorating the ecology due to human activities in a large array
of industrial and agricultural sectors. Bioassay of polluted waters using bioluminescent bacterium
has been touted as one of the most economical, rapid and sensitive tests. The growth of the
bacterium on seawater medium exhibited a typical sigmoidal profile. To extract important growth
parameters useful for further modelling exercise, various primary growth models were utilized in
this study such as Modified Logistic, modified Gompertz, modified Richards, modified Schnute,
Baranyi-Roberts, von Bertalanffy, Huang and the Buchanan three-phase model. The best
performance was Huang model with the lowest value for RMSE, AICc and the highest value for
adjusted R2. The AF and BF values were also excellent for the model with their values were the
closest to 1.0. The Huang parameters, which include A or Y0 (bacterial growth lower asymptote),
μm (maximum specific bacterial growth rate), l (lag time) and Ymax (bacterial growth upper
asymptote) were 7.866 (95% confidence interval of 7.850 to 7.883), 0.329 (95% confidence
interval of 0.299 to 0.359), 1.543 (95% confidence interval of 1.303 to 1.784) and 8.511 (95%
confidence interval of 0.299 to 0.359).
The issue of heavy metal contamination and toxic xenobiotics has become a rapid global
concern. This has ensured that the bioremediation of these toxicants, which are being carried out
using novel microbes. A bacterium with the ability to reduce molybdenum has been isolated
from contaminated soils and identified as Serratia marcescens strain DR.Y10. The bacterium
reduced molybdenum (sodium molybdate) to molybdenum blue (Mo-blue) optimally at pHs of
between 6.0 and 6.5 and temperatures between 30°C and 37°C. Glucose was the best electron
donor for supporting molybdate reduction followed by sucrose, adonitol, mannose, maltose,
mannitol glycerol, salicin, myo-inositol, sorbitol and trehalose in descending order. Other
requirements include a phosphate concentration of 5 mM and a molybdate concentration of
between 10 and 30 mM. The absorption spectrum of the Mo-blue produced was similar to the
previously isolated Mo-reducing bacterium and closely resembles a reduced phosphomolybdate.
Molybdenum reduction was inhibited by Hg (ii), Ag (i), Cu (ii), and Cr (vi) at 78.9, 69.2, 59.5
and 40.1%, respectively. We also screen for the ability of the bacterium to use various organic
xenobiotics such as phenol, acrylamide, nicotinamide, acetamide, iodoacetamide, propionamide,
acetamide, sodium dodecyl sulfate (SDS) and diesel as electron donor sources for aiding
reduction. The bacterium was also able to grow using amides such as acrylamide, propionamide
and acetamide without molybdenum reduction. The unique ability of the bacterium to detoxify
many toxicants is much in demand, making this bacterium a vital means of bioremediation.