Zinc and sulfur functionalized biochar as a peroxydisulfate activator via deferred ultraviolet irradiation for tetracycline removal.

To enhance the degradation of tetracycline class (TC) residuals of high-concentration from pharmaceutical wastewater, a novel zinc (Zn) and sulfur (S) functionalized biochar (SC-Zn), as a peroxydisulfate (PDS) activator, was prepared by two-step pyrolysis using ZnSO4 accumulated water-hyacinth. Results showed that the removal rate of 50, 150, and 250 mg per L TC reached 100%, 99.22% and 94.83% respectively, by the SC-Zn/PDS system at a dosage of 0.3 g per L SC-Zn and 1.2 mM PDS, via the deferred ultraviolet (UV) irradiation design. Such excellent performance for TC removal was due to the synergetic activation of PDS by the biochar activator and UV-irradiation with biochar as a responsive photocatalyst. The functionalization of the co-doped Zn and S endowed the biochar SC-Zn with a significantly enhanced catalytic performance, since Zn was inferred to be the dominant catalytic site for SO4˙- generation, while S played a key role in the synergism with Zn by acting as the primary adsorption site for the reaction substrates. The employed SC-Zn/PDS/UV system had excellent anti-interference under different environmental backgrounds, and compared with the removal rate of TC by adsorption of SC-Zn, the increasing rate in the SC-Zn/PDS/UV system (18.75%) was higher than the sum of the increases in the SC-Zn/PDS (9.87%) and SC-Zn/UV systems (3.34%), furtherly verifying the systematic superiority of this synergy effect. This study aimed to prepare a high-performance functionalized biochar activator and elucidate the rational design of deferred UV-irradiation of PDS activation to efficiently remove high-concentration antibiotic pollutants.

Full-Chain FeCl3 Catalyzation Is Sufficient to Boost Cellulase Secretion and Cellulosic Ethanol along with Valorized Supercapacitor and Biosorbent Using Desirable Corn Stalk.

Cellulosic ethanol is regarded as a perfect additive for petrol fuels for global carbon neutralization. As bioethanol conversion requires strong biomass pretreatment and overpriced enzymatic hydrolysis, it is increasingly considered in the exploration of biomass processes with fewer chemicals for cost-effective biofuels and value-added bioproducts. In this study, we performed optimal liquid-hot-water pretreatment (190 °C for 10 min) co-supplied with 4% FeCl3 to achieve the near-complete biomass enzymatic saccharification of desirable corn stalk for high bioethanol production, and all the enzyme-undigestible lignocellulose residues were then examined as active biosorbents for high Cd adsorption. Furthermore, by incubating Trichoderma reesei with the desired corn stalk co-supplied with 0.05% FeCl3 for the secretion of lignocellulose-degradation enzymes in vivo, we examined five secreted enzyme activities elevated by 1.3-3.0-fold in vitro, compared to the control without FeCl3 supplementation. After further supplying 1:2 (w/w) FeCl3 into the T. reesei-undigested lignocellulose residue for the thermal-carbonization process, we generated highly porous carbon with specific electroconductivity raised by 3-12-fold for the supercapacitor. Therefore, this work demonstrates that FeCl3 can act as a universal catalyst for the full-chain enhancement of biological, biochemical, and chemical conversions of lignocellulose substrates, providing a green-like strategy for low-cost biofuels and high-value bioproducts.

Challenges and perspectives of green-like lignocellulose pretreatments selectable for low-cost biofuels and high-value bioproduction.

Lignocellulose represents the most abundant carbon-capturing substance that is convertible for biofuels and bioproduction. Although biomass pretreatments have been broadly applied to reduce lignocellulose recalcitrance for enhanced enzymatic saccharification, they mostly require strong conditions with potential secondary waste release. By classifying all major types of pretreatments that have been recently conducted with different sources of lignocellulose substrates, this study sorted out their distinct roles for wall polymer extraction and destruction, leading to the optimal pretreatments evaluated for cost-effective biomass enzymatic saccharification to maximize biofuel production. Notably, all undigestible lignocellulose residues are also aimed for effective conversion into value-added bioproduction. Meanwhile, desired pretreatments were proposed for the generation of highly-valuable nanomaterials such as cellulose nanocrystals, lignin nanoparticles, functional wood, carbon dots, porous and graphitic nanocarbons. Therefore, this article has proposed a novel strategy that integrates cost-effective and green-like pretreatments with desirable lignocellulose substrates for a full lignocellulose utilization with zero-biomass-waste liberation.

LsNRL4 enhances photosynthesis and decreases leaf angles in lettuce.

Lettuce (Lactuca sativa) is one of the most important vegetables worldwide and an ideal plant for producing protein drugs. Both well-functioning chloroplasts that perform robust photosynthesis and small leaf angles that enable dense planting are essential for high yields. In this study, we used an F2 population derived from a cross between a lettuce cultivar with pale-green leaves and large leaf angles to a cultivar with dark-green leaves and small leaf angles to clone LsNRL4, which encodes an NPH3/RPT2-Like (NRL) protein. Unlike other NRL proteins in lettuce, the LsNRL4 lacks the BTB domain. Knockout mutants engineered using CRISPR/Cas9 and transgenic lines overexpressing LsNRL4 verified that LsNRL4 contributes to chloroplast development, photosynthesis and leaf angle. The LsNRL4 gene was not present in the parent with pale-green leaves and enlarged leaf angles. Loss of LsNRL4 results in the enlargement of chloroplasts, decreases in the amount of cellular space allocated to chloroplasts and defects in secondary cell wall biosynthesis in lamina joints. Overexpressing LsNRL4 significantly improved photosynthesis and decreased leaf angles. Indeed, the plant architecture of the overexpressing lines is ideal for dense planting. In summary, we identified a novel NRL gene that enhances photosynthesis and influences plant architecture. Our study provides new approaches for the breeding of lettuce that can be grown in dense planting in the open field or in modern plant factories. LsNRL4 homologues may also be used in other crops to increase photosynthesis and improve plant architecture.

Insights into pectin dominated enhancements for elimination of toxic Cd and dye coupled with ethanol production in desirable lignocelluloses.

Pectin is a minor wall polysaccharide with potential applications for bioproducts. Despite the application of specific plants and biomass-based sorbents for environmental remediation, little has been reported about characteristic roles of pectin. Using the natural rice mutant (Osfc16) treated with Cd, this study explored that pectin could predominately enhance Cd accumulation with lignocellulose, mainly due to remarkably raised uronic acids deposition. The Cd-treatment further reduced lignocellulose recalcitrance for significantly enhanced biomass saccharification and bioethanol production along with almost complete Cd release. Using all remaining fermentation rice residues that are of typical ribbon-structure and large surface, this study generated novel biosorbents by optimal chemical oxidation with the pectin extraction from citrus peels, and examined consistently raised Cd and methylene blue (MB) adsorption capacities. Therefore, this work has proposed a mechanism model about multiple pectin enrichment roles for Cd and MB removals in agricultural and industry locations with full lignocellulose utilization towards bioethanol production.

Arabidopsis thaliana branching enzyme 1 is essential for amylopectin biosynthesis and cesium tolerance.

Arabidopsis thaliana BRANCHING ENZYME 1 (AtBE1) is a chloroplast-localized embryo-lethal gene previously identified in knockout mutants. AtBE1 is thought to function in carbohydrate metabolism; however, this has not been experimentally demonstrated. Chlorosis is a typical symptom of cesium (Cs) toxicity in plants. The genetic target of Cs toxicity is largely unknown. Here, we isolated a Cs+-tolerant and chlorophyll-defective Arabidopsis ethyl methanesulfonate (EMS) mutant, atbe1-5. Mapping by sequencing and genetic complementation confirmed that a single amino acid change (P749S) in a random coil motif of AtBE1 confers the mutant's Cs+-tolerant and chlorophyll-defective phenotype. An isothermal titration calorimetry assay determined that the 749th residue is the Cs+-binding site and hence likely the target of Cs+ toxicity. We hypothesized that binding of Cs+ to the 749th residue of AtBE1 inhibits the enzyme's activity and confers Cs+ toxicity, which in turn reduces photosynthetic efficiency. In support with this hypothesis, atbe1-5 leaves have a reduced photosynthetic efficiency, and their amylose and amylopectin contents are ∼60 % and ∼1%, respectively, of those in Col-0 ecotype leaves. Leaves of the mutant have a lower sucrose, but higher maltose, concentration than those of Col-0. This study demonstrated that AtBE1 is an essential gene for amylopectin and amylose biosynthesis, as well as the target of Cs+ toxicity; therefore, it can serve as a genetic locus for engineering plants to extract Cs+ from contaminated soil while maintaining growth.

A mechanism for efficient cadmium phytoremediation and high bioethanol production by combined mild chemical pretreatments with desirable rapeseed stalks.

Cadmium (Cd) is one of the most hazardous trace metals, and rapeseed is a major oil crop over the world with considerable lignocellulose residues applicable for trace metal phytoremediation and cellulosic ethanol co-production. In this study, we examined that two distinct rapeseed cultivars could accumulate Cd at 72.48 and 43.70 ug/g dry stalk, being the highest Cd accumulation among all major agricultural food crops as previously reported. The Cd accumulation significantly increased pectin deposition as a major factor for trace metal association with lignocellulose. Meanwhile, the Cd-accumulated rapeseed stalks contained much reduced wall polymers (hemicellulose, lignin) and cellulose degree of polymerization, leading to improved lignocellulose enzymatic hydrolysis. Notably, three optimal chemical pretreatments were performed for enhanced biomass enzymatic saccharification and bioethanol production by significantly increasing cellulose accessibility and lignocellulose porosity, along with a complete Cd release for collection and recycling. Hence, this study proposed a mechanism model interpreting why rapeseed stalks are able to accumulate much Cd and how the Cd-accumulated stalks are of enhanced biomass saccharification. It has also provided a powerful technology for both cost-effective Cd phytoremediation and value-added bioethanol co-production with minimum waste release.

DNA mismatch repair related gene expression as potential biomarkers to assess cadmium exposure in Arabidopsis seedlings.

In the current study, Arabidopsis seedlings were hydroponically grown on MS media containing cadmium (Cd) of 0-2.0 mg L(-1) for 60 h of treatment. Gene expression profiles were used to relate exposure to Cd with some altered biological responses and/or specific growth effects. RT-PCR analysis was used to quantitate mRNA expression for seven genes known to be involved in DNA mismatch repair (MMR) system and cell division. Results indicated that Cd concentrations of 0.25-2.0 mg L(-1) cause increased total soluble protein levels in shoots of Arabidopsis seedlings in an inverted U-shaped dose-response manner. Exposure to 0.25 and 0.5 mg L(-1) of Cd dramatically induced expression of four genes (i.e. proliferating cell nuclear antigen 2 (atPCNA 2), MutL1 homolog (atMLH1), MutS 2 homolog (atMSH2) and atMSH3) and five genes (i.e. atPCNA1,2, atMLH1 and atMSH2,7), respectively, in shoots of Arabidopsis seedlings; Exposure to 1.0 mg L(-1) of Cd significantly elevated expression of only two genes (atMSH6,7), but caused prominent inhibition in expression of three genes (atPCNA2, atMLH1 and atMSH3) in shoots of Arabidopsis seedlings. The expression alterations of the above genes were independent of any biological effects such as survival, fresh weight and chlorophyll level of shoots. However, shoots of Arabidopsis seedlings exposed to 2.0 mg L(-1) of Cd exhibited statistically prominent repression in expression of these seven genes, and showed incipient reduction of fresh weight and chlorophyll level. This research provides data concerning sensitivity of expression profiles of atMLH1, atMSH2,3,6,7 and atPCNA1,2 genes in Arabidopsis seedlings to Cd exposure, as well as the potential use of these gene expression patterns as representative molecular biomarkers indicative of Cd exposure and related biological effects.