5 results about "Polymalic acid" patented technology

The invention discloses a modified aureobasidium pullulans strain based on reduction of malic acid pathway consumption and application of the modified aureobasidium pullulans strain. Gene for coding NADPH dependent malic enzyme and phosphoenolpyruvate carboxykinase in an aureobasidium pullulans genome is directionally knocked out. The transformation blocks a key consumption branch for synthesis and accumulation of the cytoplasmic malic acid, and effectively guides a central carbon metabolic flow to be more efficiently guided to a target product. Experimental results show that the polymalic acid yield and the saccharic acid conversion rate of the double-knockout engineering strain D3N5-delta3617 / deltapepck in fermentation are remarkably improved compared with those of an original strain, and the biomass is also increased. The invention provides a high-performance strain with important application value for industrial efficient fermentation production of polymalic acid.

The application discloses synergistically modified ethyne carbon black by poly malic acid and KH550, a preparation method and application thereof, and the method comprises the following steps: blending poly malic acid, gamma-aminopropyl triethoxysilane and ethyne carbon black in a mass ratio of (0.5-5):(1-10):100, and then performing reaction to obtain ethyne carbon black synergistically modified by poly malic acid and gamma-aminopropyl triethoxysilane. The ethyne carbon black is synergistically modified by poly malic acid and gamma-aminopropyl triethoxysilane (KH550), an esterification reaction occurs between the carboxyl in the poly malic acid molecule and the surface hydroxyl of the ethyne carbon black, meanwhile, a hydroxylamino reaction occurs between the amino group of the KH550 and the hydroxyl, and an amide bond bridge is formed between the poly malic acid and the KH550, thereby realizing ternary synergistic covalent modification. The structure effectively improves the dispersion stability of the ethyne carbon black, the chain-like or grape-like high specific surface area structure of the ethyne carbon black can be fully utilized, the ethyne carbon black is more uniformly dispersed in a polymer matrix, and the interface is more closely combined.

Disclosed in the present invention are a cross-linked polyamide hydrogel material and a preparation method therefor. The hydrogel is obtained by means of a cross-linking reaction between a water-soluble polyamide and a cross-linking agent. The water-soluble polyamide comprises poly(malic acid-spermidine), poly(malic acid-spermine), poly(succinic acid-spermidine), or poly(succinic acid-spermine). The cross-linking agent is an endogenous dibasic acid. The cross-linking reaction means that after being activated by a catalyst, a carboxyl group on the endogenous dibasic acid undergoes a two-step activation cross-linking reaction with an imine group on the backbone of the polyamide to obtain the hydrogel. The present invention prepares the hydrogel by means of a two-step activation cross-linking technique. By means of the cross-linking technique, the amounts of the catalyst and the cross-linking agent can be reduced, and hydrogels having different properties can also be prepared by controlling the type of the cross-linking agent and cross-linking conditions, thereby improving the cross-linking reaction efficiency and achieving the control of the degradation rate of the hydrogel and the release rate of an active monomer, exhibiting broad application prospects.

The application relates to the technical field of polymer synthesis, in particular to an initiation / catalyst and a preparation method and application thereof, polylactic acid-poly(malic acid) and a preparation method and application thereof. The application provides an initiation / catalyst, and the preparation raw materials include 4-hydroxymethyl benzoic acid and 1,8-diazabicyclo[5.4.0]undec-7-ene. The initiation / catalyst has the advantage of weakened biological toxicity in biological medicine compared with a metal catalyst which is traditionally adopted.

The invention discloses a cross-linked polyamide hydrogel material and a preparation method thereof. The hydrogel is obtained by carrying out a cross-linking reaction on water-soluble polyamide and a cross-linking agent; the water-soluble polyamide comprises poly (malic acid-spermidine), poly (malic acid-spermine), poly (succinic acid-spermidine) or poly (succinic acid-spermine), and the cross-linking agent is endogenous binary acid; the cross-linking reaction refers to that carboxyl on the endogenous binary acid is activated by a catalyst and then is subjected to two-step activation cross-linking reaction with imino on a polyamide main chain to obtain the hydrogel. The hydrogel is prepared by adopting a two-step activation cross-linking technology, the cross-linking technology can reduce the dosage of a catalyst and a cross-linking agent, the hydrogel with different properties can be prepared by controlling the variety of the cross-linking agent and the cross-linking condition, the cross-linking reaction efficiency is improved, the degradation rate of the hydrogel and the release rate of the active monomer are controlled, and the cross-linking efficiency is improved. And the method has a very good application prospect.