Efficiently coupled glucose oxidation for high-value D-glucaric acid with ultradurable hydrogen via Mn(III)in acidic solution

The electrooxidation of the alcohol and aldehyde molecules instead of water coupled with H2 production has been proven to be effective for producing high-value fine chemicals under alkaline conditions.It is also noteworthy that under acidic conditions,the stability of non-noble metal water oxidation catalysts remains a great challenge due to the lattice oxygen mechanism.Hence,we coupled the biomass-derived glucose oxidation for high-value D-glucaric acid(GRA)with ultra-durable hydrogen in acid solution over a Yb-MnO_(2)catalyst.The Mn^(3+)regulated by Yb atoms doped in MnO_(2)can effectively optimize the adsorption and desorption processes of the alcohol and aldehyde group and improve the intrinsic activity but cannot for H2O.The catalyst exhibited extremely high activity and stability after 50 h for glucose oxidation,inhibiting the lattice oxygen process and MnO4−formation,while the activity was quickly lost within 0.5 h for water oxidation.Density functional theory(DFT)calculations further demonstrated that glucose oxidation reaction proceeds preferentially due to the oxidation of aldehyde group with lower adsorption-free energy(−0.4 eV)than water(ΔG>0 eV),avoiding the lattice oxygen mechanism.This work suggests that biomass-derived glucose oxidation not only provides a cost-effective approach for high-value chemicals,but also shows an extremely potential as an alternative to acidic oxygen evolution reaction(OER)for ultradurable H2 production.

土壤中聚乙烯降解菌的筛选、鉴定及降解特性

【目的】农用地膜主要成分为聚乙烯(polyethylene,PE),因其难以被降解,其废弃物常造成"白色污染",本研究从常年覆盖农用地膜的土壤中筛选PE降解菌,并探究其对PE制品的降解效能。【方法】采集的土壤样品用PE为唯一碳源的无机盐培养基进行富集,筛选、纯化PE降解菌,分离菌通过形态染色、生理生化特征、16S rRNA基因序列分析进行鉴定,检测其在不同PE浓度(0%、0.05%、0.10%、0.25%、0.50%、1.00%、2.00%、3.00%)的无机盐培养基中的生长曲线,最后通过扫描电镜、光镜观察,检测分离菌对农用地膜的降解效能。【结果】从土壤中筛选获得一株能够降解PE的分离菌株(命名为SW1),初步鉴定其为放线菌的诺卡氏菌属Nocardia sp.。SW1的生长对PE具有明显浓度依赖,在含2%PE的无机盐培养基中生长最快,在培养的第48 h菌液浓度开始明显增加,第60 h达到最大,而在不含PE的无机盐培养基中未见生长。形态生理学观察表明,35°C培养15d后,扫描电镜观察可见有大量菌嵌入膜内或附于膜表面生长,膜表面粗糙,并开始出现破损;培养60 d后,光镜观察可见膜大面积破损,并出现空洞。【结论】从土壤中筛选获得了一株能够有效降解PE制品的放线菌菌株Nocardia sp. SW1。该研究丰富了PE制品降解微生物的菌种资源,为PE塑料废弃物的生物降解提供了科学数据与参考。