A new paradigm in lignocellulolytic enzyme cocktail optimization: Free from expert-level prior knowledge and experimental datasets.

Effectively pairing diverse lignocellulolytic enzyme cocktails with intricately structured lignocellulosic substrates is an enduring challenge for science and technology. To date, extensive trial-and-error remains the primary approach and no deep-learning methods were developed to address it due to limited experimental data and incomplete expert-level knowledge of enzyme-cocktail-substrate structure-dynamics-function relationships. Here, a novel model is developed to tackle this issue in efficient, cost-effective, and high-throughput manners. It needs no pre-labeled datasets, instead utilizing simple features, eliminating the reliance on expert-level prior knowledge of reaction mechanisms. Experimentally optimal combinations were found within predicted ranges of tailor-made combinations with precision of 91.98%, covering 80.00% of overall top-100. Practical tests demonstrated its effectiveness in narrowing down potential optimal combinations, speeding up targeted screening, and enabling efficient degradation of lignocellulosic biomass. The method has good applications in artificial proteins biosynthesis from low-value lignocellulosic straw, providing alternative solutions for biomass biorefining challenges in complex enzyme-cocktail-substrate interactions.

Atomically dispersed Fe/Bi dual active sites single-atom nanozymes for cascade catalysis and peroxymonosulfate activation to degrade dyes.

Constructing single-atom nanozymes (SAzymes) with densely exposed and dispersed double metal-Nx catalytic sites for pollution remediation remains rare and challenging. Herein, we report a novel Fe-Bi bimetallic MOF-derived carbon supported Fe-N4 and Bi-N4 dual-site FeBi-NC SAzyme for cascade catalysis and peroxymonosulfate activation to degrade dye pollutants, which is synthesized from the Fe-doped Bi-MOF as a precursor. The formation of both Fe-N4 and Bi-N4 sites is demonstrated by XANES and EXAFS. The FeBi-NC SAzyme has high single atoms loadings of Fe (2.61 wt%) and Bi (8.01 wt%), and displays 5.9- and 9.8-fold oxidase mimicking activity enhancement relative to the Fe-NC and Bi-NC SAzymes, respectively. When integrated acetylcholinesterase (AChE) and FeBi-NC SAzyme, a cascade enzyme-nanozyme system is developed for selective and sensitive screening of AChE activity with a low detection limit of 1 × 10-4 mU mL-1. Both Fe-N4 and Bi-N4 in FeBi-NC display a strong binding energy and electron donating capability to promote peroxymonosulfate activation to generate highly active intermediates for rhodamine B degradation. 100% rhodamine B removal occurs within 5 min via FeBi-NC mediated activation of peroxymonosulfate. The DFT calculations reveal that high activity of FeBi-NC is due to the isolated Fe-N4 and Bi-N4 sites and their synergy.

Promoting Active Sites in MOF-Derived Homobimetallic Hollow Nanocages as a High-Performance Multifunctional Nanozyme Catalyst for Biosensing and Organic Pollutant Degradation.

Nanozymes are one of the ideal alternatives to natural enzymes for various applications. The rational design of nanozymes with improved catalytic activity stimulates increasing attention to address the low activity of current nanozymes. Here, we reported a general strategy to fabricate the Co-based homobimetallic hollow nanocages (HNCs) (C-CoM-HNC, M = Ni, Mn, Cu, and Zn) by ion-assistant solvothermal reaction and subsequent low-temperature calcination from metal-organic frameworks. The C-CoM-HNCs are featured with HNCs composed of interlaced nanosheets with homogeneous bimetallic oxide dispersion. The hierarchical structure and secondary metallic doping endow the C-CoM-HNC highly active sites. In particular, the Cu-doped C-CoCu-HNCs nanostructures exhibit superior performances over the other C-CoM-HNC as both the oxidase mimicking and peroxymonosulfate (PMS) activator. A sensitive bioassay for acetylcholinesterase (AChE) was established based on the excellent oxidase-like activity of C-CoCu-HNC, offering a linear detection range from 0.0001 to 1 mU/mL with an ultralow detection limit of 0.1 mU/L. As the PMS activator, the C-CoCu-HNC was applied for targeted organic pollutant (rhodamine B, RhB) degradation. A highly efficient RhB degradation was realized, along with good adaptability in a wide pH range and good reusability during the eight-cycle run. The results suggest that C-CoCu-HNC holds a practical potential for clinical diagnostics and pollution removal. Further density functional theory calculation reveals that Cu doping leads to a tighter connection and more negative adsorption energy for O2/PMS, as well as an upshifted d-band center in the C-CoCu-HNCs nanostructures. These changes facilitated the adsorption of O2/PMS on the C-CoCu-HNC surface for dissociation. This work not only offers a promising multifunctional nanozyme catalyst for clinical diagnostics and pollution removal but also gives some clues for the further development of novel nanozymes with high catalytic activities.