文献综述
Summary of IntroductionnBiocatalytic reduction of biomass-derived 5-hydroxymethylfurfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) is considered as a sustainable method and has attracted great attention. Biocatalytic upgrading of due to the product specificity, mild reaction and high efficiency. Biocatalytic reduction of furfural and 5-hydroxymethylfurfural to furfural alcohol and 2, 5-Bis (hydroxymethyl), is Currently of great interest. This Review critically discusses the recent progresses and advances about bio-reduction of furfural and 5-hydroxymethylfurfural by whole cells and enzymes. BHMF is the hydrogenation product of the formyl group in HMF and is a versatile building block for the synthesis of polymers,[1] drugs,[2] Macrocycle polyether compounds,[3] and crown ethers. And also, Furfuryl alcohol is an important intermediate for the production of thermostatic resins, synthetic fibers, farm chemicals, and plasticizers.[4] It is well known that furfural is a much stronger inhibitory compound to microorganisms than HMF. As we see how BHMF is important so developing an efficient and selective biocatalytic approach for the synthesis of 2,5-bis(hydroxymethyl)furan (BHMF) from 5-hydroxymethylfurfural (HMF) It attracts the attention of many researchers and workers in this field.Biocatalytic reduction of HMF to BHMF can be conducted by using isolated enzymes. And also, can be conducted theoretically using isolated oxidoreductases as well as whole cell. Conducted by using isolated enzymes has some disadvantages. Compared to isolated oxidoreductases, so whole cells were preferable for HMF reduction because they are not only inexpensive, and more stable but also do not require complex cofactor regeneration systems that are necessary for isolated enzymes.[23]. There are some reports on whole cell-catalyzed Transformation of HMF in the literature, [22f, 25,]. In which 2,5-Furandicarboxylic acid (FDCA) was synthesized by oxidation of HMF. Some microorganisms were reported to be capable of Transforming HMF in biological detoxification of the inhibitors Present in lignocellulosic hydrolysates.[26] However, efficient synthesis of BHMF from HMF using whole Cells is still a great challenge because the substrate HMF is A well-known potent inhibitor to microorganisms.[24] for example themicroorganisms that werereported to be capable of Transforming HMF in biological detoxification of the inhibitors Present in lignocellulosic hydrolysates[26] were not appropriate biocatalysts for efficient Synthesis of BHMF from HMF because Their biodetoxification efficiencies remained low,[27]) Their tolerance to HMF, especially in High concentrations, was poor [26c, d],the selectivities were not satisfactory; in addition to BHMF,The oxidation products of HMF were also formed.[27b, 28] . Recently was reported a new highly HMF tolerant yeast strainMeyerozyma guilliermondii SC1103 was Isolated, and biocatalytic reduction of HMF to 2,5-bis(hydroxymethyl)furan (BHMF) using its resting cells was reported. Cosubstrates exerted a significant effect on the catalytic activity and selectivity of microbial cells as well as their HMF-tolerant Levels whereas the nitrogen source and mineral salts had no effects. In addition, M. guilliermondii SC1103 cells exhibited good Catalytic performances within the range of pH 4.010.0. The Yeast was highly tolerant to both HMF (up to 110 mm) and BHMF (up to 200 mm). In addition, 100 mm HMF could be selectively reduced to BHMF within 12 h by its resting cells in the Presence of 100 mm glucose (as cosubstrate), with a yield of 86% and selectivity of >99%. The production of 191 mm of BHMF was realized within 24.5 h by using a fed-batch strategy, With a productivity of approximately 24 gL1 per day[46]. 2 _Furfuryl alcohol (FA) is the most important derivative of furfural, since approximately 65% of furfural produced worldwide is utilized for the synthesis of FA [29,31]. FA has been used widely in polymer, food, and pharmaceutical industries [29,31]. FA is primarily used in the production of thermostatic resins, corrosion resistant fiber glass, and polymer concrete [32]. In addition, it is a building block in the manufacture of fragrances and pharmaceuticals, and for the synthesis of useful chemicals, such as tetrahydrofurfuryl alcohol, ethyl furfuryl ether, levulinic acid, and γ-valerolactone [31].The industrial large-scale production of FA from furfural is performed over Cu-based catalysts, especially Cu-Cr catalysts, in gas or liquid phase [31]. Although the industrial routes have been well-established, they suffer from some problems, such as catalyst deactivation, serious environmental problems (due to the high toxicity of chromium), and overreduction of the desired product (thus leading to the formation of 2-methylfuran and furan) [30,31,33]. To address the drawbacks, chemists have devoted great efforts in the last decades. Significant advances have been achieved in the chemical catalytic hydrogenation of furfural to FA. A variety of new chemical catalysts, as well as efficient reaction engineering strategies, have also been developed to improve the production of this commercially important chemical [29,31,34]. Biotransformation is generally performed under mild conditions and is exquisitely selective, and biocatalysts are environmentally friendly [35]. Hence, biocatalysis represents a promising strategy for upgrading bio-based furans such as HMF and furfural [36], because of the inherent instability of these chemicals. Nevertheless, biocatalytic upgrading of these furans remains a great challenge, since they are proverbial inhibitors against enzymes and microorganisms [37]. Previously, many microorganisms (e.g., bacteria and yeasts) were reported to enable the detoxification of furfural into less toxic FA during the fermentation of biofuels and chemicals from lignocellulosic hydrolysates [3839]. However, these reported microbes exhibited an unsatisfactory furan tolerance, and the biotransformation efficiencies were very low, especially at moderate to high substrate concentrations [40,41]. High substrate concentrations are highly desired for achieving satisfactory productivities in the biocatalytic synthesis of FA, which is crucial for moving these kinds of green technologies toward and into successful applications. Recently, we isolated Meyerozyma guilliermondii SC1103 from soil for the reduction of furans, including HMF and furfural [44]. A chemo-enzymatic method was reported for the synthesis of FA from xylose by Hes group [42,43], in which the intermediate furfural derived from xylose was reduced into FA by a group of recombinant Escherichia coli strains. Interestingly, some E. coli strains exhibited good catalytic performances when the furfural concentrations were up to 200300 mM [42,43]. Recently, Yan et al. reported the synthesis of FA using Bacillus coagulans NL01 [45]; the furfural tolerance of this bacterium (less than 50 mM) was unsatisfactory, although the conversion of 92% and the selectivity of 96% were obtained.
以上是毕业论文文献综述，课题毕业论文、任务书、外文翻译、程序设计、图纸设计等资料可联系客服协助查找。
