Modeling applications have rarely been employed despite them allowing a more detailed picture of the anaerobic digestion

system Copyright (c) 2012 Society of Chemical Industry”
“BACKGROUND: Saccharomyces cerevisiae is one of the main microorganisms that can produce S-adenosylmethionine (SAM) Compound C solubility dmso from L-methionine and ATP with high productivity. To satisfy the ATP requirement for SAM synthesis, sufficient oxygen should be supplied to the medium to improve aerobic metabolism in S. cerevisiae. In this study, n-hexadecane used as oxygen vector for enhancement of SAM production by this yeast was investigated. RESULTS: N-hexadecane was most favorable for cell growth and BTSA1 SAM synthesis in S. cerevisiae when added at the time of inoculation. It could increase glucose consumption,

reduce ethanol accumulation, and ultimately improve biomass and SAM productivity in a fermentation process. In a bioreactor, the highest yield of SAM (2.27 g L-1) was achieved in the presence of 4% (v/v) n-hexadecane after 24 h of inoculation, which was 23.37% higher than the control (1.84 g L-1). CONCLUSION: The addition of n-hexadecane to cultures of S. cerevisiae significantly enhanced SAM production without increasing energy consumption, and has the potential for use in large-scale fermentation processes to increase oxygen supply. Copyright (c) 2012 Society of Chemical find more Industry”
“BACKGROUND: TiO2 heterogeneous photocatalysis should be optimized before application for the removal of pollutants in treated wastewaters. The response surface methodology (RSM) and artificial neural networks (ANNs) were applied to model and optimize the photocatalytic degradation of total phenolic (TPh) compounds in real secondary and tertiary treated

municipal wastewaters. RESULTS: RSM was developed by considering a central composite design (CCD) with three input variables, i.e. TiO2 mass, initial concentration of TPh and irradiation intensity. At the same time a feed-forward multilayered perceptron ANN trained using back propagation algorithms was used and compared with RSM. Under the optimum conditions established in experiments ([TPh]0 = 3 mg L-1; [TiO2] = 300 mg L-1; I = 600 W m-2) the degradation for both TPh and total organic carbon (TOC) followed pseudo-first-order kinetic model. Complete degradation of TPh took place in 180 min and reduction of TOC reached 80%. A significant abatement of the overall toxicity was accomplished as revealed by Microtox bioassay. CONCLUSIONS: It was found that the variables considered have important effects on TPh removal efficiency. The results demonstrated that the use of experimental design strategy is indispensable for successful investigation and adequate modeling of the process and that ANNs gave better modelling capability than RSM.