1.In situ butanol recovery from Clostridium acetobutylicum fermentations by expanded bed adsorption.
Wiehn M1, Staggs K, Wang Y, Nielsen DR. Biotechnol Prog. 2014 Jan-Feb;30(1):68-78. doi: 10.1002/btpr.1841. Epub 2013 Nov 30.
Although butanol is a promising biofuel, its fermentative production suffers from inhibition caused by end product toxicity. The in situ removal of butanol from cultures via expanded bed adsorption offers an effective strategy for mitigating the effects of product toxicity while eliminating the need to clarify cultures via microfiltration. The hydrophobic polymer resin Dowex Optipore L-493 was found to be both an effective butanol adsorbent and suitable for use in expanded bed adsorption. Recirculation rates through the adsorption column were strongly correlated with and ultimately controlled rates of butanol uptake from the media which, reaching as high as 41.1 g/L h, easily exceed those of its production in a typical fermentation. Vacuum application with vapor collection was found to be an effective means of adsorbent regeneration, with an average of 81% butanol recovery possible, with butanol concentrations in the cold trap reaching as high as 85.
2.Determination of copper, lead and iron in water and food samples after column solid phase extraction using 1-phenylthiosemicarbazide on Dowex Optipore L-493 resin.
Yildiz O1, Citak D, Tuzen M, Soylak M. Food Chem Toxicol. 2011 Feb;49(2):458-63. doi: 10.1016/j.fct.2010.11.024. Epub 2010 Nov 25.
A novel solid phase extraction procedure for determination of copper, lead and iron in natural water and food samples has been established in the presented work. 1-Phenylthiosemicarbazide (1-PTSC) as ligand and Dowex Optipore L-493 resin as adsorbent were used in a mini chromatographic column. Various analytical conditions for the quantitative recoveries of analyte ions including pH, amounts of adsorbent, eluent, sample volume, etc. were investigated. The recovery values for analyte ions were higher than 95%. The determination of copper, lead and iron was performed by flame atomic absorption spectrometry. The influences of some alkali, alkali earth and transition metals on the recoveries of analyte ions were investigated. The preconcentration factor was 62.5. The limit of detections of the understudied analytes (k=3, N=21) were 0.64 μg L(-1) for copper, 0.55 μg L(-1) for lead and 0.82 μg L(-1) for iron. The relative standard deviation was found to be lower than 6%.