The synthesis of fine chemicals using multi-enzyme cascade reactions is a recent hot research topic in the field of biocatalysis. The traditional chemical synthesis methods were replaced by constructing in vitro multi-enzyme cascades, then the green synthesis of a variety of bifunctional chemicals can be achieved. This article summarizes the construction strategies of different types of multi-enzyme cascade reactions and their characteristics. In addition, the general methods for recruiting enzymes used in cascade reactions, as well as the regeneration of coenzyme such as NAD(P)H or ATP and their application in multi-enzyme cascade reactions are summarized. Finally, we illustrate the application of multi-enzyme cascades in the synthesis of six bifunctional chemicals, including ω-amino fatty acids, alkyl lactams, α, ω-dicarboxylic acids, α, ω-diamines, α, ω-diols, and ω-amino alcohols.
Amino Acids ; Biocatalysis ; Amino Alcohols ; Coenzymes/metabolism* ; Diamines

NAD(P)(H)-dependent oxidoreductase catalyzes the reduction of ketones or aldehydes to prepare a wide variety of valuable chiral alcohols or amines. However, expensive cofactors are absolutely required for the biocatalytic processes with oxidoreductases, which severely hinder their industrial applications. Consequently, the issue on reducing cofactor costs has become one of the major focuses in the field of biocatalysis. With the substantial development in recent years, a number of strategies have been proposed and implemented to solve the cofactor issues in the oxidoreductase catalyzed biocatalysis, including the establishment of cofactor regeneration system, the improvement of endogenous cofactor availability via metabolic engineering and the development of biomimetic agents to replace cofactors. In this review, recent trends and advances on these strategies are presented, and respective advantages and shortcomings are also discussed with a number of examples.
Alcohols ; metabolism ; Biocatalysis ; Ketones ; metabolism ; Metabolic Engineering ; NADH, NADPH Oxidoreductases ; metabolism ; Oxidation-Reduction

Higher alcohols have a high energy density, low hygroscopicity and can be mixed with gasoline at any ratio. It is the trend to replace fossil fuels with biofuels produced via microbial fermentation of renewable resources. We reviewed the progress in the development of engineered Saccharomyces cerevisiae and Escherichia coli that can produce higher alcohols, as well as the related technology platforms. We mainly focused on the construction of CoA-dependent pathways and alpha-keto acid mediated non-fermentative pathways, analyzed their respective characteristics, and summarized the construction strategies. The problems to be solved and future research direction were also discussed.
Alcohols ; metabolism ; Escherichia coli ; genetics ; metabolism ; Industrial Microbiology ; methods ; Metabolic Engineering ; methods ; Saccharomyces cerevisiae ; genetics ; metabolism

The conversion of exogenous p-hydroxybenzaldehyde to p-hydroxy-methyl-phenol-beta-D-glucoside (gastrodin) was studied by using cell suspension culture of Datura tatula L. The chemical structure of this synthesized gastrodin was identified based on the spectral analysis and chemical evidence. The conversion procedure of p-hydroxybenzaldehyde into gastrodin by D. tatula L. cell suspension cultures was established. The synthesized gastrodin (II) was isolated from the ferment liquor and identified by spectral analysis. At the same time, the p-hydroxybenzyl alcohol (I) converted through biotransformation of p-hydroxybenzaldehyde by cell suspension cultures of D. tatula L. was also isolated and identified. The efficiency of glucosylation of p-hydroxybenzaldehyde was remarkably enhanced by adding salicylic acid (0.1 mg/L) and keeping the lower pressure (0.001MPa) in 25L airlift loop bioreactor. The biotransformation of exogenous p-hydroxybenzaldehyde to gastrodin by cell suspension culture of D. tatula L. is a promising approach.
Benzaldehydes ; metabolism ; Benzyl Alcohols ; chemistry ; Bioreactors ; Biotransformation ; Datura ; metabolism ; Glucosides ; biosynthesis ; chemistry ; Salicylic Acid ; pharmacology ; Suspensions

Higher alcohols are one of the main by-products of Saccharomyces cerevisiae in brewing. High concentration of higher alcohols in alcoholic beverages easily causes headache, thirst and other symptoms after drinking. It is also the main reason for chronic drunkenness and difficulty in sobering up after intoxication. The main objective of this review is to present an overview of the flavor characteristics and metabolic pathways of higher alcohols as well as the application of mutagenesis breeding techniques in the regulation of higher alcohol metabolism in S. cerevisiae. In particular, we review the application of metabolic engineering technology in genetic modification of amino transferase, α-keto acid metabolism, acetate metabolism and carbon-nitrogen metabolism. Moreover, key challenges and future perspectives of realizing optimization of higher alcohols metabolism are discussed. This review is intended to provide a comprehensive understanding of metabolic regulation system of higher alcohols in S. cerevisiae and to provide insights into the rational development of the excellent industrial S. cerevisiae strains producing higher alcohols.
Alcoholic Beverages ; Alcohols/analysis* ; Fermentation ; Saccharomyces cerevisiae/metabolism* ; Saccharomyces cerevisiae Proteins/metabolism*

As an important active ingredient in the rare Chinese herb Gastrodiae Rhizoma and also the main precursor for gastrodin biosynthesis, 4-hydroxybenzyl alcohol has multiple pharmacological activities such as anti-inflammation, anti-tumor, and anti-cerebral ischemia. The pharmaceutical products with 4-hydroxybenzyl alcohol as the main component have been increasingly favored. At present, 4-hydroxybenzyl alcohol is mainly obtained by natural extraction and chemical synthesis, both of which, however, exhibit some shortcomings that limit the long-term application of 4-hydroxybenzyl alcohol. The wild and cultivated Gastrodia elata resources are limited. The chemical synthesis requires many steps, long time, and harsh reaction conditions. Besides, the resulting by-products are massive and three reaction wastes are difficult to treat. Therefore, how to artificially prepare 4-hydroxybenzyl alcohol with high yield and purity has become an urgent problem facing the medical researchers. Guided by the theory of microbial metabolic engineering, this study employed the genetic engineering technologies to introduce three genes ThiH, pchF and pchC into Escherichia coli for synthesizing 4-hydroxybenzyl alcohol with L-tyrosine. And the fermentation conditions of engineering strain for producing 4-hydroxybenzyl alcohol in shake flask were also discussed. The experimental results showed that under the conditions of 0.5 mmol·L~(-1) IPTG, 15 ℃ induction temperature, and 40 ℃ transformation temperature, M9 Y medium containing 200 mg·L~(-1) L-tyrosine could be transformed into(69±5)mg·L~(-1) 4-hydroxybenzyl alcohol, which has laid a foundation for producing 4-hydroxybenzyl alcohol economically and efficiently by further expanding the fermentation scale in the future.
Benzyl Alcohols ; Escherichia coli/metabolism* ; Gastrodia/chemistry* ; Metabolic Engineering ; Tyrosine/metabolism*

Alcohols ; metabolism ; Bioreactors ; microbiology ; History, 20th Century ; Microbiology ; history ; Molasses ; microbiology

Basidiomycete PM2, a lignin-degrading white rot fungus, produces lgnin peroxidase (Lip) and manganese peroxidase (Mnp) in nutrient nitrogen limited liquid cultures. This fungus was selected for its ability to decolorize azo group of dyes. In order to improve production of the peroxidases and rapid dye decolorizing activity by basidiomycete PM2, the addition of veratryl alcohol or Tween 80 to nutrient nitrogen limited liquid cultures were tested. It was found to have a large stimulatory effect on Mnp activities and decolorization rate of azo dyes. A maximum Mnp activities of 254.2 u/L with veratryl alcohol and 192.2 u/L with Tween 80 were achieved respectively. These values were about 3.4-fold and 2.5-fold higher than that obtained in the control cultures (without alcohol or Tween 80), whereas the levels of Lip activity detected were very low (about 12 u/L)in all the cultures. In further experiments using three kinds of azo dyes of congo red, orange G and orange IV, enzyme activities and dye decolorization were investigated in the above-mentioned cultures. The results showed that Mnp activities and decolorization were notably higher than those obtained in the control cultures in the presence of azo dyes. Cultures supplemented with Tween 80 were more adequate for dye decolorization. The rates of the decolorization with Tween 80 of congo red (95.4%), orange G (98.5%) and orange IV (54.4%) after 24 hours of dye incubation were higher than that supplemented with veratryl alcohol. According to the results, Mnp activities secreted by basidiomycete PM2 play an essential role in the process of dye decolorization. Tween 80 was the main factor affecting the decolorization. The analysis of structure of the three kinds of azo dyes indicats that the extent of decolorization is affected by the dye molecular structure. The types and quantity of the substituted groups on the aromatic ring of azo dyes have effect on the percentage of biological decolorization.
Azo Compounds ; metabolism ; Basidiomycota ; enzymology ; metabolism ; Benzyl Alcohols ; pharmacology ; Coloring Agents ; metabolism ; Oxygenases ; biosynthesis ; Peroxidases ; biosynthesis ; Polysorbates ; pharmacology

OBJECTIVETo study on the drug release characteristics and mechanism of gastrodin ion-activated nasal in situ gel in vitro.

METHODRegularity and mechanism of the drug release of gastrodin nasal in situ gel were studied by using the diffusion cell model and the membrane-less dissolution model, respectively. A novel kinesis diffusion cell model was designed according to the characteristics of release environment of nasal cavity. It was used to investigate the effect of adhesiveness on the release of the in situ gel.

RESULTDrug release of gastrodin nasal in situ gel followed the one order release model. Erosion rate of the gel was low and not linearly correlated with the release rate. Compared with gastrodin solution, the nasal in situ gel could increase release time and release amount.

CONCLUSIONGastrodin in the nasal in situ gel is released mainly by diffusion rather than erosion. Release amount of the in situ gel in nasal cavity may be obviously increased because of its adhesiveness.

Adhesiveness ; Benzyl Alcohols ; chemistry ; metabolism ; Calibration ; Diffusion ; Gels ; Glucosides ; chemistry ; metabolism ; Kinetics ; Models, Chemical ; Nose ; metabolism ; Solubility

To determine the concentration of gastrodigenin in tissue homogenates with high performance liquid chromatography (HPLC) , in order to study the changes of the distribution of gastrodigenin before and after combined application in rat tissues, including heart, liver, spleen, lung, kidney and brain tissues. The study showed that gastrodigenin could be found in kidney, liver, heart, lungs, spleen and brain tissues. After the combined application of Gastrodiae Rhizoma and Ligustici Wallichii Rhizoma, the content of gastrodigenin decreased in kidney and liver to varying degrees, while increasing in lung and brain. This indicated that Ligustici Wallichii Rhizoma had certain impact on the in vivo distribution of gastrodigenin, an active ingredient in Gastrodiae Rhizoma, because it could improve gastrodigenin's distribution in lung and brain tissues. The study provides scientific basis for the combined application of Gastrodiae Rhizoma and Ligustici Wallichii Rhizoma in treating brain diseases.
Animals ; Benzyl Alcohols ; metabolism ; pharmacokinetics ; Brain ; metabolism ; Chromatography, High Pressure Liquid ; Female ; Gastrodia ; chemistry ; Kidney ; metabolism ; Ligusticum ; chemistry ; Liver ; metabolism ; Lung ; metabolism ; Male ; Rats ; Spleen ; metabolism