Production of l-tryptophan by enantioselective hydrolysis of d,l-tryptophanamide using a newly isolated bacterium

Abstract

Bacterial strain ZJB-09211 capable of amidase production has recently been isolated from soil samples. The strain is able to asymmetrically hydrolyze l-tryptophanamide from d,l-tryptophanamide to produce l-tryptophan in high yield and with excellent stereoselectivity (enantiomeric excess > 99.9 %, and enantiomeric ratio > 200). Strain ZJB-09211 has been identified as Flavobacterium aquatile based on the cell morphology analysis, physiological tests, and the 16S rDNA sequence analysis. Optimization of the fermentation medium led to an about six-fold increase in the amidase activity of strain ZJB-09211, which reached 501.5 U L−1. Substrate specifity and stereoselectivity investigations revealed that amidase of F. aquatile possessed a broad substrate spectrum and high enantioselectivity.

MnCo2O4 Nanowires Anchored on Reduced Graphene Oxide Sheets as Effective Bifunctional Catalysts for Li–O2 Battery Cathodes

“…The reversibled ischarge capacity of 1000 mA hg carbon À1 was maintained over 35 cycles for the MCO@RGO catalyst in the O 2 cathode, whereas the Li-O 2 cells with pure KB and MCO NWs underwent ap otentialp olarization during subsequent cycles and then showedd rastic capacity fades after the 13th and 25th cycles, respectively.T he O 2 electrode with the MCO@RGO catalystc ould have more catalyticallya ctive sites and facilitatet he transfer rates of electrons and oxygen atoms and, thus, couldd ecrease the charge-discharge overpotential andi mprove discharge-charge round-trip efficiency. [52][53][54] To elucidate the reversibility of Li-O 2 cells with the catalysts for repeated cycles, potential versus time profiles are provided in FigureS7. Note that the discharge potential profile of the O 2 electrode with MCO@RGO catalysts was maintained to 400 h(%35 cycles), which indicates the outstanding cyclability of the O 2 electrode with the MCO@RGOc atalyst, whereas discharge potentiald rops to 2.3 Vw ereo bserved after 300 and 275 hf or the O 2 electrodes with pure KB and MCO NWs, respectively.…”

Survey on the theoretical research and engineering applications of multivariate statistics process monitoring algorithms: 2008–2017

“…The MSPM algorithms have a wide range of applications, including chemical processes, [105] manufacturing processes, [106] mechanical processes, [107] electrical power systems, [108] and fan main control systems. [109] Besides industrial processes, researchers also applied them to special problems, such as daily sleep monitoring, [110] glucose monitoring, [111] and monitoring of vital human body signals. [112] Patents in Web of Science Table 10 lists the number of patents related to the commonly used MPSM algorithms such as PCA, PLS, ICA, and GMM.…”

Efficient racemization of N‐phenylacetyl‐D‐glufosinate for L‐glufosinate production

“…As the basic units of protein, amino acids are widely used in pharmaceutical, food, and cosmetics industries . Most amino acids contain chiral centres and exist as two enantiomers, D‐ and L‐, which have different or even opposite physiological activities . L‐amino acids can be directly utilized by organisms, so they play an important role in the feed industry .…”

“…1 Most amino acids contain chiral centres and exist as two enantiomers, D-and L-, which have different or even opposite physiological activities. 2 L-amino acids can be directly utilized by organisms, so they play an important role in the feed industry. 3 As important raw materials in the pharmaceutical and food fields, D-amino acids and their derivatives are widely used in the synthesis of semisynthetic antibiotics, peptide hormones, pyrethroids, insecticides, and sweeteners.…”