Aim: To increase the transformation rate of L L-sorbose to 2-keto-L L-gulonic (2-KLG) acid in a two-step process of L L-ascrobic acid manufacture by ion beam. Methods and Results: Gluconobacter oxydans (GO29) and Bacillus megaterium (BM80) were used in the present study. Ion implantation was carried out with the heavy ion implantation facility at the institute of Plasma Physics in China. 2-KLG in whole culture broth was determined by iodometry. Mutants were screened by singlecolony isolation and 2-KLG accumulation in broth. GO29 and BM80 were implanted by either hydrogen ions (H + ) or nitrogen ions (N + ) with various doses, respectively. The average transformation rate of GM112-302 bred by ion beam in Gram-molecule was increased from 79AE3 to 94AE5% after eight passages in shaking flasks. Furthermore, in 180-ton fermentors in Jiangsu Jiangshan Pharmaceutical Co. Ltd, the transformation rate was stable at 92AE0%, indicating a producer could get 0AE99 kg of gulonic acid from 1AE0 kg of sorbose. Conclusion: Ion beam as a new mutation source had potential advantages in breeding. Comparing with original mixture GO29 and BM80, GM112-302 is more efficient in accumulating 2-KLG, especially at the later phase. Significance and Impact of the Study: GM112-302 bred by ion beam implantation dramatically increased the transformation rate by 19AE2%, which greatly increased efficiency and reduced the cost of L L-ascorbic acid manufacture in a two-step process.

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The reaction of vinyl radical with molecular oxygen in solid argon has been studied using matrix isolation infrared absorption spectroscopy. The vinyl radical was produced through high frequency discharge of ethylene. The vinyl radical reacted with oxygen spontaneously on annealing to form the vinylperoxy radical C(2)H(3)OO with the O-O bond in a trans position relative to the C-C bond, which is characterized by O-O stretching and out-of-plane CH(2) bending vibrations at 1140.7 and 875.5 cm(-1). The vinylperoxy radical underwent visible photon-induced dissociation to the CH(2)OH(CO) complex or CH(2)OH+CO, which has never been considered in previous studies. The CH(2)OH(CO) product was predicted to be more thermodynamically accessible than the previously reported major HCO+H(2)CO channel, and is most likely produced by hydrogen atom transfer from the first-formed H(2)CO-HCO pair in solid argon.

Reactions of titanium dioxide with acetylene molecules have been studied using matrix isolation infrared absorption spectroscopy. The titanium dioxide molecules were prepared by the reactions of laser-ablated titanium atoms with dioxygen. In solid argon, titanium dioxide molecule reacted with acetylene to form the TiO 2 -C 2 H 2 complex spontaneously on annealing. The complex underwent photochemical rearrangement to the OTi(OH)CCH and H 2 Ti(CO) 2 isomers upon UV-visible photolysis. The product absorptions were identified by isotopic substitutions and density functional calculations of isotopic frequencies.

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