Medium optimization for endochitinase production by recombinant Pichia pastoris ZJGSU02 using response surface methodology

Plackett-Burman design and response surface methodology were employed to optimize the medium components for endochitinase production by Pichia pastoris. A Plackett- Burman design of seven factors with 12 runs was applied to evaluate the effects of different medium components. Yeast extract, oleic acid and Tween-80 were found to have significant influence on endochitinase production. The optimal concentrations of three factors were investigated by the response surface methodology using Box- Behnken design. The optimal medium components obtained for achieving the maximum activity of the endochitinase were as follows: Yeast extract 24.36 g/l, tryptone 20 g/l, YNB 5.0 g/l, potassium phosphate 100 mM, methanol 5 ml/l, oleic acid 1.758 ml/l, Tween-80 6.2 ml/l, Pichia trace metals (PTM1) 4.0 ml/ l and biotin 4.00 × 10-4 g/l. Under these conditions, endochitinase activity was up to 88.26 μ/ml, which was about 1.14-fold higher than using the original medium (77.62 μ/ml). This work will be very helpful for large-scale production of endochitinase for future industrial application.Keywords: Recombinant endochitinase, Plackett-Burman design, response surface methodology, fermentatio

catena-Poly[[trimeth­yl(4-sulfanylphen­yl)aza­nium] [(chloridocadmate)-di-μ-chlorido]]

The title compound, {(C9H14NS)[CdCl3]}n, consists of a linear [CdCl3]nn − polyanion and a trimeth­yl(4-sulfanylphen­yl)aza­nium cation. The CdII atom is penta­coordinated by four μ2-Cl atoms and one terminal Cl atom in a trigonal–bipyramidal geometry. The trigonal–bipyramidal units are linked by two opposite shared faces, giving rise to infinite [CdCl3]n chains parallel to the a axis. The cations surround the chain and are linked to them by S—H⋯Cl and C—H⋯Cl hydrogen bonds, forming a three-dimensional network

(S)-1-Hydroxy­propan-2-aminium (2R,3R)-3-carb­oxy-2,3-dihydroxy­propanoate monohydrate

The chiral title compound, C4H10NO+·C4H5O6 −·H2O, is a hydrated mol­ecular salt in which the tartaric acid has transferred one proton to the (S)-2-amino­propan-1-ol mol­ecule. The crystal structure is stabilized by a three-dimensional network of N—H⋯O and O—H⋯O hydrogen bonds. The absolute configuration was assigned on the basis of the starting materials