CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Wenyu Zhang,Shuguang Xu,Yuan Xiao,Diyan Qin,Jianmei Li,Changwei Hu
The unique properties of rare earth metal offer attractive potentials for the application as catalyst in biomass valorization. In present work, we found that rare earth metal ions exhibited specific catalytic activity for lactic acid production from biomass, giving 75.9% and 71.0% carbon molar yield of lactic acid from glucose and furfural residue, respectively. The activity of lanthanide(III) ions increased monotonically with the atomic number, as well as the decreasing ionic radius, from La 3+ to Lu 3+ . The increasing oxidation potential with atomic number might facilitate the disproportionation reaction in glucose conversion via an intramolecular H-shift. DFT calculation further revealed that smaller ionic radius of lanthanide(III) ions led to stronger interaction between lanthanide(III) ions and glucose/fructose, as well as the less composition of 4 f in LUMO that enabled more activation of glucose. More importantly, lanthanide(III) with smaller ionic radius exhibited higher electron-withdrawing ability from the oxygen atom in -C = O. This enhanced the electrophilicity of C2, C3, and C4 atoms, and led to the more exposure especially for C4 atom, thereby significantly weakening C3-C4 bond. In addition to the increasing orbital-stabilization ability at the bond-breaking site in the corresponding transition state with atomic number, the energy barrier for C3-C4 cleavage in fructose was greatly reduced by heavy lanthanide(III) ions. These factors contributed to the special activity for lactic acid formation from biomass. The insights in this work might give some useful clues for the widespread application of rare earth metal in biomass valorization.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
JOURNAL OF BIOTECHNOLOGY
·
2015
·
IF 2.871
Xia Yi,Peng Zhang,Jiaoe Sun,Yi Tu,Qiuqiang Gao,Jian Zhang,Jie Bao
Pediococcus acidilactici TY112 producing l -lactic acid and P. acidilactici ZP26 producing d -lactic acid, were engineered from the wild-type P. acidilactici DQ2 by ldhD or ldh gene disruption , and the robustness of the wild-type strain to the inhibitors derived from lignocellulose pretreatment was maintained well. In simultaneous saccharification and fermentation (SSF), 77.66 g L −1 of l -lactic acid and 76.76 g L −1 of d -lactic acid were obtained at 25% (w/w) solids content of dry dilute acid pretreated and biodetoxified corn stover feedstock. l - and d -Lactic acid yield and productivity were highly dependent on the inhibitor removal extent due to the significant down-regulation on the expressions of ldh and ldhD encoding lactate dehydrogenase by inhibitor, especially syringaldehyde and vanillin at the low concentrations. This study provided a prototype of industrial process for high titer l - and d -lactic acid production from lignocellulose feedstock.
研究领域:
微生物工程
·
生物化学工程
✓ 已验证
DOI
高影响因子
METABOLIC ENGINEERING
·
2024
·
IF 6.8
Yajing Zhang,Tao Sun,Linqi Liu,Xupeng Cao,Weiwen Zhang,Wangyin Wang,Can Li
Microbial CO 2 fixation into lactic acid (LA) is an important approach for low-carbon biomanufacturing. Engineering microbes to utilize CO 2 and sugar as co-substrates can create efficient pathways through input of moderate reducing power to drive CO 2 fixation into product. However, to achieve complete conservation of organic carbon, how to engineer the CO 2 -fixing modules compatible with native central metabolism and merge the processes for improving bioproduction of LA is a big challenge. In this study, we designed and constructed a solar formic acid/pentose (SFAP) pathway in Escherichia coli , which enabled CO 2 fixation merging into sugar catabolism to produce LA. In the SFAP pathway, adequate reducing equivalents from formate oxidation drive glucose metabolism shifting from glycolysis to the pentose phosphate pathway. The Rubisco-based CO 2 fixation and sequential reduction of C3 intermediates are conducted to produce LA stoichiometrically. CO 2 fixation theoretically can bring a 20% increase of LA production compared with sole glucose feedstock. This SFAP pathway in the integration of photoelectrochemical cell and an engineered Escherichia coli opens an efficient way for fixing CO 2 into value-added bioproducts.
研究领域:
合成生物学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF BIOSCIENCE AND BIOENGINEERING
·
2016
·
IF 1.964
Zijian Zhao,Xiaona Xie,Zhi Wang,Yanchun Tao,Xuedun Niu,Xuri Huang,Li Liu,Zhengqiang Li
Lactic acid bacteria immobilization methods have been widely used for lactic acid production. Until now, the most common immobilization matrix used is calcium alginate . However, Ca-alginate gel disintegrated during lactic acid fermentation . To overcome this deficiency, we developed an immobilization method in which Lactobacillus rhamnosus cells were successfully encapsulated into an ordered mesoporous silica-based material under mild conditions with a high immobilization efficiency of 78.77% by using elemental analysis. We also optimized the cultivation conditions of the immobilized L. rhamnosus and obtained a high glucose conversion yield of 92.4%. Furthermore, L. rhamnosus encapsulated in mesoporous silica-based material exhibited operational stability during repeated fermentation processes and no decrease in lactic acid production up to 8 repeated batches.
研究领域:
微生物学
·
生物工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
3 Biotech
·
2024
·Vol. 15
·期 1
·1-8
·
IF 2.6
Feng Xinming,Cui Xinyu,Wang Kun,Liu Juanjuan,Meng Dongdong
6-Phosphogluconate dehydrogenases (6PGDHs) are widely existing as reduced cofactor (NADH/NADPH) regeneration biocatalysts. Herein, a thermostable 6PGDH from Hydrogenobacter thermophilus (Ht6PGDH) was overexpressed in Escherichia coli and enzymologically characterized. Ht6PGDH exhibited exceptional stability and catalytic activity under high-temperature conditions, with an optimum temperature of 85 °C and the ability to maintain high activity for prolonged periods at 70 °C, which could be purified through a one-step heat treatment. Moreover, Ht6PGDH exhibited a preference for NAD + with a K m value of 0.4 mM and a k cat value of 28.6 s⁻ 1 , demonstrating a significant preference over NADP + . These properties render Ht6PGDH a potentially valuable enzyme for high-temperature bioconversion and in vitro synthetic biosystems. Additional research showed that Ht6PGDH excelled in the regeneration of NADH, achieving efficient lactate production when integrated into an in vitro synthetic biosystem containing lactate dehydrogenase (LDH). Furthermore, the cascade reaction of Ht6PGDH with glucose-6-phosphate dehydrogenase (G6PDH) was explored for NADH regeneration using starch as the substrate, further validating its potential application in complex biosynthetic systems.
研究领域:
生物化学
·
酶工程
·
合成生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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