Biosynthesis of 3-hydroxypropionic acid from 1,3-propanediol by Gluconobacter oxydans ZJB09112 / 生物工程学报

3-Hydroxypropionic acid is an important building block to synthesize lots of industrially valuable chemicals. In this study, we firstly investigated the effects of cell, substrate and product concentrations on biosynthesis of 3-hydroxypropionic acid from 1,3-propanediol by Gluconobacter oxydans ZJB09112 in 50-mL shake flask containing 10 mL transformation liquid. To avoid the inhibition of substrate and product, we adopted fed-batch biotransformation and fed-batch biotransformation coupled with in situ product removal in 2-L bubble column reactor containing 1 L transformation liquid. The results show that high concentrations of substrate and product could inhibit the biotransformation by decreasing the initial reaction rate, and the optimal reaction conditions were as follows: cell concentration 6 g/L, pH 5.5. Fed-batch biotransformation in which the substrate concentration was maintained at 15-20 g/L could obtain product concentration of 60.8 g/L after 60 h, which gave a productivity of 1.0 g/(Lh) and a yield of 84.3%. Furthermore, fed-batch biotransformation coupled with in situ product removal could achieve the total product concentration of 76.3 g/L after 50 h, which gave a productivity of 1.5 g/(L x h) and a yield of 83.7%. The results obtained here may be useful for the application of G. oxydans in biocatalysis industry by using its characteristic of incomplete oxidation of alcohols.

Research progress of layer-by-layer self-assembly technique in drug delivery / 药学学报

Now the layer-by-layer self-assembling (LbL) technique has become an attention-getting reparative methodology for ultrathin film formation. Many scientists in different academic areas including bioengieering, medical science, drug controlled release, optoelectronics dive into this technology. Among of them, carriers with structures which can be flexibly controlled are more useful since functional structure units can be assembled in layer-by-layer fashion, which is simplicity, chemical mildness, concealment, can achieve targeted drug delivery and so on. In this review, we have discussed the advantage, development, influential factors and applications of LbL. We have focused on reviewing the applications and perspective of nanoparticles, microgels and capsules were both fabricated via the LbL assembling at drug delivery.