Higher Product Yield Research Articles

Nitrogen affects the grain quality and antioxidant response of super rice varieties of fragrant and non-fragrant genotypes under different planting methods

The fragrant genotype of super rice contributed to the high yield, superior quality and strong aroma in rice production. The different responses of super rice varieties of fragrant and non-fragrant genotypes to nitrogen fertilization and planting methods are still unclear. A two-year field experiment was conducted to investigate the effects of nitrogen fertilizer and planting methods on the head rice yield, quality, photosynthesis and biomass of fragrant (Yuxiangyouzhan) and non-fragrant (Jiyou615) genotypes of super rice. The results revealed that the head rice yield and grain quality of Yuxiangyouzhan were greater than those of Jiyou615. Increased nitrogen fertilization significantly improved the grain quality of both cultivars, with greater improvement in Jiyou615. Yuxiangyouzhan presented the highest head rice yield, milling quality, and protein content under HT, followed by under MD, and Jiyou615 presented the highest under MT and MD. Both cultivars had higher amylose content and lower alkali under MD. Grain quality differences were attributed to the effects of nitrogen and planting method on photosynthesis and biomass. Nitrogen fertilizer and planting method promoted increased biomass and rates of grain filling through enhanced photosynthesis, which ultimately led to improved head rice yield and milling quality and a harder texture in both cultivars. Additionally, N2 application increased the 2-AP content of YXYZ under MD, which may be related to the effects of antioxidant enzymes on proline content. Considering the cost, we concluded that 220 kg hm−2 of nitrogen fertilizer application under MD improved the quality and aroma of the fragrant genotype of super rice.

Evaluation of Modified Conventional Still Distiller Using Coupled External Passive Condenser: An Experimental Study

Solar radiation plays an important part in the desalination of saline water owing to its abundance in areas with potable water shortage and it also occupies a paramount place in green energy generation due to its simplicity of application. Still distiller is viewed by researchers as a suitable source of potable water because of low cost of fabrication, easy operation and zero emission technology. Studies by researchers are geared towards exploring new models to improve the productivity of solar stills and enhance its production rate is ongoing. The main aspiration of this work is to experiment the consequence of introducing a passive condenser to a modified conventional solar still to enhance its productivity yield. It was observed that the modified passive still distiller coupled with the external condenser gave about 11.85% higher production yield in comparison with the modified conventional still distiller. Daily and accumulated distillate yield for the still distillers have been studied and analyzed. The result of the findings revealed that sawdust padding around the still distillers is recommended to maximize productivity leading to efficient water distillation in regions where that require still distiller usage. This recommendation has been seen to produce the desired result in accessing to potable water within areas where water scarcity prevails. This is suggested to contribute effectively bearing the cost ineffective water desalination technique.

Isolation and characterization of a resistance Bacillus subtilis for soil stabilization and dust alleviation purposes

Dust poses environmental, geological, health, and economic concerns, and microorganisms can help mitigate these adverse consequences by improving soil properties. Microbial calcium carbonate precipitation (MICP) has been found to be an efficient strategy for increasing soil strength, reducing soil porosity, and preventing erosion; however, severe environmental conditions such as pH and high temperatures may impede this process. To identify the best strain for MICP, 60 bacteria strains were obtained from arid soils using the enrichment culture technique. They were tested for the capacity of calcium carbonate deposition and biocement synthesis in stress environments. Phenotypic characterization indicated that the majority of the bacterial isolates were gram-positive and rod-shaped, with strong catalase and oxidase enzyme activity. Furthermore, MALDI-TOF MS identification revealed that the isolates were from the Bacillus and Pseudomonas genera. Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were used to analyze the microstructures and composition of bacterial cement. The results represented that B. subtilis isolate S56 has a higher production yield and forms distinctive calcite crystals as a result of fast urease synthesis. B. subtilis isolate S56 can be applied in situ to reduce soil erosion and dust pollution. This study reveals the potential of the B. subtilis S56 strain for soil consolidation and dust prevention in harsh environments and has the prospect of promoting its application in desertification control and ecological restoration.

Optimized Phosphorus Application Enhances Wheat Stem Lodging Resistance Under Spring Low-Temperature Stress.

Spring low-temperature stress (LTS) has become a major limiting factor for the development of high yield, quality and efficiency in wheat production. It not only affects the function of wheat leaves and the development of spikes but also impacts stem lodging resistance, and may experience elevated risk of stem lodging. This study conducted a field pot experiment to assess the effect of phosphorus fertilizer application mode on wheat stem lodging resistance under spring LTS. Two wheat varieties, Yannong19 (YN19, cold-tolerant variety) and Xinmai26 (XM26, cold-sensitive variety) used as the experiment material. Two phosphorus fertilizer application models including traditional phosphorus application (TPA) and optimized phosphorus application (OPA) were employed. Temperature treatment was conducted at 15 °C (CK) and -4 °C (LT) in a controlled phytotron. Our results showed that spring LTS decreased the stem wall thickness and internode fullness, and altered stem anatomical structure and chemical composition, resulting in a decrease in wheat stem mechanical strength and lodging resistant index. Compared with TPA, the OPA increased the stem wall thickness and internode fullness. The thickness of the stem mechanic tissue layer and parenchymatous tissue, and the area of the large vascular bundle and small vascular bundle were increased by the OPA, which alleviated the damage to stem cell walls caused by spring LTS. At the same time, the OPA also increased the contents of lignin, cellulose, and soluble sugar, improving the C/N ratio in wheat stem. Due to the improved stem morphological characteristics, anatomical structure, and chemical compositions, the wheat stem exhibited enhanced lodging resistance, which increased the lodging resistant index of the 2nd and 3rd internodes of YN19 and XM26 by 27.27%, 11.63% and 14.15%, 15.73% at the dough stage compared with TPA under spring LTS. Meanwhile, OPA could not only alleviate the yield loss caused by spring LTS, but also increase the grain yield without spring LTS. This study indicated that OPA enhances wheat stem lodging resistance under spring LTS, and would be meaningful and practical for improving wheat resistance to low-temperature stress.

The Optimal Drought Hardening Intensity and Salinity Level Combination for Tomato (Solanum lycopersicum L.) Cultivation under High-Yield, High-Quality and Water-Saving Multi-Objective Demands.

The extreme weather and the deteriorating water environment have exacerbated the crisis of freshwater resource insufficiency. Many studies have shown that salty water could replace freshwater to partly meet the water demand of plants. To study the effects of early-stage drought hardening and late-stage salt stress on tomatoes (Solanum lycopersicum L.), we conducted a 2-year pot experiment. Based on the multi-objective demands of high yield, high quality, and water saving, yield indicators, quality indicators, and a water-saving indicator were selected as evaluation indicators. Three irrigation levels (W1: 85% field capacity (FC), W2: 70% FC, W3: 55% FC) and three salinity levels (S2: 2 g/L, S4: 4 g/L, S6: 6 g/L) were set as nine treatments. In addition, a control treatment (CK: W1, 0 g/L) was added. Each treatment was evaluated and scored by principal component analysis. The results for 2022 and 2023 found the highest scores for CK, W2S2, W3S2 and CK, W2S4, W2S2, respectively. Based on response surface methodology, we constructed composite models of multi-objective demands, whose results indicated that 66-72% FC and 2 g/L salinity were considered the appropriate water-salt combinations for practical production. This paper will be beneficial for maintaining high yield and high quality in tomato production using salty water irrigation.

Effect of Streptomyces costaricanus Strain A-m1 as a Bioinoculant on Tea Garden Soil and Tea Quality

Chemical fertilization is usually associated with some unreasonable problems that affect the sustainable production of tea gardens. The micro-organism fertilizer created from plant growth-promoting microbes (PGPM) integrates the beneficial properties of functional micro-organisms and bioinoculants. Application of PGPM can activate soil nutrients, prevent soil-borne diseases, and promote crop growth, thus improving crop quality and yield. In this study, the effects of bioinoculants composed of Streptomyces costaricanus strain A-m1 on the properties, enzyme activity, and micro-organisms of soil in a tea garden and on the chemical composition and production of tea were investigated. The present results showed that the application of A-m1 bioinoculant could increase the activities of urease, protease and catalase, the content of alkali-hydrolyzable nitrogen, and the number of bacteria, fungi, and actinomycetes in tea garden soil. After application, the free amino acid content, 100-bud weight, and bud density of spring tea were also elevated. In the year of fertilization, the treatment composed of 70% bioinoculant + 30% chemical fertilizer showed the best effects on soil physical and chemical properties, enzyme activity, culturable microbial counts, and tea quality. A high ratio of organic to chemical fertilizer coapplication can significantly improve the growing conditions for tea plants, reduce the use of chemical fertilizers, improve the efficiency of nutrient utilization, and enhance both the yield and quality of tea. One year after fertilization, the 50% bioinoculant + 50% chemical fertilizer was more conducive to enhancing the quality of tea, while the 30% bioinoculant + 70% chemical fertilizer was more beneficial for improving the production of tea. A high ratio of chemical to bioinoculant coapplication is more favorable for maintaining high yield and quality in tea production, achieving healthy and sustainable tea garden management. The application of A-m1 bioinoculant will reduce the use of chemical fertilizers, improve the utilization efficiency of soil nutrients, and increase the production and quality of tea, contributing to the sustainable production of tea gardens.

Enhancing Rice Cultivation Efficiency in Tidal Lowland of Delta Saleh, Indonesia: Precision Farming Practices for Water Management and Soil Health Improvement

Tidal lowland is a marginal land characterized by low pH, deficient nutrients, and salinity. Despite these challenges, El Niño phenomenon often occurs during the second planting season, resulting in long droughts. However, tidal lowland must be used for cultivation due to the need for rice and the land should be treated accurately. Therefore, this research aimed to address the issues by improving the efficiency of rice cultivation on tidal lowland through precision farming practices. A survey and land analysis were conducted in tidal lowland of B typology in Delta Saleh, Indonesia, from March 2023 to June 2023. In this precision farming practice, water management was highly prioritized, starting from tertiary channels such as optimizing sluice gate operations and monitoring water levels in channels and groundwater. Additionally, pH, CEC, and C-Organic analysis were also carried out in rice cultivation, as showed by the equation Y = 0.15 - 0.001 pH + 0.000 CEC + 0.000 C-Organic. The highest production yield was 2.05 tons/ha in P5, with the SEW-10 value during cultivation activities being 778 cm and the number of days above -10 reaching 84. Moreover, the efficiency of rice cultivation was improved through precision agricultural practices by using valve sluices and levees.

Enhancing Rice Cultivation Efficiency in Tidal Lowland of Delta Saleh, Indonesia: Precision Farming Practices for Water Management and Soil Health Improvement

Tidal lowland is a marginal land characterized by low pH, deficient nutrients, and salinity. Despite these challenges, El Niño phenomenon often occurs during the second planting season, resulting in long droughts. However, tidal lowland must be used for cultivation due to the need for rice and the land should be treated accurately. Therefore, this research aimed to address the issues by improving the efficiency of rice cultivation on tidal lowland through precision farming practices. A survey and land analysis were conducted in tidal lowland of B typology in Delta Saleh, Indonesia, from March 2023 to June 2023. In this precision farming practice, water management was highly prioritized, starting from tertiary channels such as optimizing sluice gate operations and monitoring water levels in channels and groundwater. Additionally, pH, CEC, and C-Organic analysis were also carried out in rice cultivation, as showed by the equation Y = 0.15 - 0.001 pH + 0.000 CEC + 0.000 C-Organic. The highest production yield was 2.05 tons/ha in P5, with the SEW-10 value during cultivation activities being 778 cm and the number of days above -10 reaching 84. Moreover, the efficiency of rice cultivation was improved through precision agricultural practices by using valve sluices and levees.

Effects of physical property dynamic change on heat transfer characteristics of coal seam during in-situ pyrolysis of tar-rich coal

Tar-rich coal has the features of high tar yield and great potential for oil production. The underground in-situ pyrolysis technology is an effective way to accomplish the green and efficient utilization of tar-rich coal resources. The pore structures of coal seam have great change in the actual in-situ pyrolysis process. Hence, the physical properties of coal seam also vary with pyrolysis temperature, which affects the heat transfer performance of coal seam. However, previous studies on heat transfer characteristics of coal seam have been seldom paid attention to the physical property dynamic change during the in-situ pyrolysis, which possibly causes deviation between the simulated heat transfer characteristics and the actual performance. It is still unclear whether the deviation is acceptable in practical engineering practice at present. In this article, a modification scheme for the physical property dynamic change of coal seam was proposed. The effects of physical property dynamic change on heat transfer characteristics of coal seam during in-situ pyrolysis of tar-rich coal were analyzed using numerical simulation approach. In addition to single factor correction, the effects of three-factor coupling modification on heat transfer performance of coal seam were also systematically investigated. The simulation results indicated that both the average temperature and the effective heating area of the coal seam increased after the specific heat capacity was corrected individually. Whereas, the heat transfer of coal seam was weakened after the endothermic effect of pyrolysis and the thermal conductivity coefficient were modified, respectively. When the three factors were coupled for correction in the single well and single fracture mode, the correction factor that played a leading role was the thermal conductivity coefficient, accounting for 90%. However, an increase in the number of cracks enhanced the heat transfer, resulting in the specific heat capacity was dominant among the three correction factors. The present study can offer theoretical guidance and technical support for realizing large-scale in-situ pyrolysis of tar-rich coal.

Structure-Function Relationship of p-Block Bismuth for Selective Photocatalytic CO2 Reduction.

Selective photocatalytic reduction of CO2 to value-added fuels, such as CH4, is highly desirable due to its high mass-energy density. Nevertheless, achieving selective CH4 with higher production yield on p-block materials is hindered by non-ideal adsorption of *CHO key intermediate and an unclear structure-function relationship. Herein, we unlock the key reaction steps of CO2 and found a volcano-type structure-function relationship for photocatalytic CO2-to-CH4 conversion by gradual reduction of the p-band center of the p-block Bi element leading to formation of Bi-oxygen vacancy heterosites. The selectivity of CH4 is also positive correlation with adsorption energy of *CHO. The Bi-oxygen vacancy heterosites with an appropriate filled Bi-6p orbital electrons and p band center (-0.64) enhance the coupling between C-2p of *CHO and Bi-6p orbitals, thereby resulting in high selectivity (95.2 %) and productivity (17.4 μmol g-1 h-1) towards CH4. Further studies indicate that the synergistic effect between Bi-oxygen vacancy heterosites reduces Gibbs free energy for *CO-*CHO process, activates the C-H and C=O bonds of *CHO, and facilitates the enrichment of photoexcited electrons at active sites for multielectron photocatalytic CO2-to-CH4 conversion. This work provides a new perspective on developing p-block elements for selective photocatalytic CO2 conversion.

Structure‐Function Relationship of p‐Block Bismuth for Selective Photocatalytic CO2 Reduction

AbstractSelective photocatalytic reduction of CO2 to value‐added fuels, such as CH4, is highly desirable due to its high mass‐energy density. Nevertheless, achieving selective CH4 with higher production yield on p‐block materials is hindered by non‐ideal adsorption of *CHO key intermediate and an unclear structure‐function relationship. Herein, we unlock the key reaction steps of CO2 and found a volcano‐type structure‐function relationship for photocatalytic CO2‐to‐CH4 conversion by gradual reduction of the p‐band center of the p‐block Bi element leading to formation of Bi‐oxygen vacancy heterosites. The selectivity of CH4 is also positive correlation with adsorption energy of *CHO. The Bi‐oxygen vacancy heterosites with an appropriate filled Bi‐6p orbital electrons and p band center (−0.64) enhance the coupling between C‐2p of *CHO and Bi‐6p orbitals, thereby resulting in high selectivity (95.2 %) and productivity (17.4 μmol g−1 h−1) towards CH4. Further studies indicate that the synergistic effect between Bi‐oxygen vacancy heterosites reduces Gibbs free energy for *CO‐*CHO process, activates the C−H and C=O bonds of *CHO, and facilitates the enrichment of photoexcited electrons at active sites for multielectron photocatalytic CO2‐to‐CH4 conversion. This work provides a new perspective on developing p‐block elements for selective photocatalytic CO2 conversion.

Root Zone Water Management Effects on Soil Hydrothermal Properties and Sweet Potato Yield.

Sufficient soil moisture is required to ensure the successful transplantation of sweet potato seedlings. Thus, reasonable water management is essential for achieving high quality and yield in sweet potato production. We conducted field experiments in northern China, planted on 18 May and harvested on 18 October 2021, at the Nancun Experimental Base of Qingdao Agricultural University. Three water management treatments were tested for sweet potato seedlings after transplanting: hole irrigation (W1), optimized drip irrigation (W2), and traditional drip irrigation (W3). The variation characteristics of soil volumetric water content, soil temperature, and soil CO2 concentration in the root zone were monitored in situ for 0-50 days. The agronomy, root morphology, photosynthetic parameters, 13C accumulation, yield, and yield components of sweet potato were determined. The results showed that soil VWC was maintained at 22-25% and 27-32% in the hole irrigation and combined drip irrigation treatments, respectively, from 0 to 30 days after transplanting. However, there was no significant difference between the traditional (W3) and optimized (W2) drip irrigation systems. From 30 to 50 days after transplanting, the VWC decreased significantly in all treatments, with significant differences among all treatments. Soil CO2 concentrations were positively correlated with VWC from 0 to 30 days after transplanting but gradually increased from 30 to 50 days, with significant differences among treatments. Soil temperature varied with fluctuations in air temperature, with no significant differences among treatments. Sweet potato survival rates were significantly lower in the hole irrigation treatments than in the drip irrigation treatments, with no significant difference between W2 and W3. The aboveground biomass, photosynthetic parameters, and leaf area index were significantly higher under drip irrigation than under hole irrigation, and values were higher in W3 than in W2. However, the total root length, root volume, and 13C partitioning rate were higher in W2 than in W3. These findings suggest that excessive drip irrigation can lead to an imbalance in sweet potato reservoir sources. Compared with W1, the W2 and W3 treatments exhibited significant yield increases of 42.98% and 36.49%, respectively. The W2 treatment had the lowest sweet potato deformity rate.

Comprehensive analyses of the ARF gene family in cannabis reveals their potential roles in regulating cannabidiol biosynthesis and male flower development.

Cannabidiol (CBD), as an important therapeutic property of the cannabis plants, is mainly produced in the flower organs. Auxin response factors (ARFs) are play a crucial role in flower development and secondary metabolite production. However, the specific roles of ARF gene family in cannabis remain unknown. In this study, various bioinformatics analysis of CsARF genes were conducted using online website and bioinformatics, quantitative real time PCR technology was used to investigate the expression patterns of the CsARF gene family in different tissues of different cannabis varieties, and subcellular localization analysis was performed in tobacco leaf. In this study, 22 CsARF genes were identified and found to be unevenly distributed across 9 chromosomes of the cannabis genome. Phylogenetic analysis revealed that the ARF proteins were divided into 4 subgroups. Duplication analysis identified one pair of segmental/whole-genome duplicated CsARF, and three pairs of tandemly duplicated CsARF. Collinearity analysis revealed that two CsARF genes, CsARF4 and CsARF19, were orthologous in both rice and soybean. Furthermore, subcellular localization analysis showed that CsARF2 was localized in the nucleus. Tissue-specific expression analysis revealed that six genes were highly expressed in cannabis male flowers, and among these genes, 3 genes were further found to be highly expressed at different developmental stages of male flowers. Meanwhile, correlation analysis between the expression level of CsARF genes and CBD content in two cultivars 'H8' and 'Y7' showed that the expression level of CsARF13 was negatively correlated with CBD content, while the expression levels of six genes were positively correlated with CBD content. In addition, most of CsARF genes were responsive to IAA treatment. Our study laid a foundation for the further studies of CsARFs function in cannabis, and provides candidate genes for breeding varieties with high CBD yield in cannabis production.

Influence of PepF peptidase and sporulation on microcin J25 production in Bacillus subtilis.

MccJ25 displays significant antibacterial activity, a well-defined mode of action, exceptional safety, and remarkable stability. Hence, it presents itself as a compelling candidate for an optimal antibacterial or anti-endotoxin medication. The successful establishment of exogenous production of MccJ25 in Bacillus subtilis provides a strategy for reducing its production cost and diversifying its utilization. In this study, we have provided evidence indicating that both peptidase PepF and sporulation are significant factors that limit the expression of MccJ25 in B. subtilis. The ΔpepF and ΔsigF mutants of B. subtilis express MccJ25 with higher production yield and enhanced stability. To sum up, this study developed several better engineered strains of B. subtilis, which greatly reduced the consumption of MccJ25 during the nutrient depletion stage of the host strain, improved its production, and elucidated factors that may be involved in reducing MccJ25 accumulation in B. subtilis.

Laser-induced graphene formation on different wood species: Dependence of electronic performance on intrinsic features of certain types of wood

Conductive, 3D, porous graphene can be produced with a CO2 laser from a large variety of materials, including wood, at room temperature, and under inert atmosphere or after treatment for fire protection. Here, we investigated the suitability for direct conversion of 46 typical European and Asian woods into laser-induced graphene (LIG), without pre-treatment. The LIG was characterized by resistance measurements to determine if a conductive layer had formed, and via Raman spectroscopy. Here, we show, for the first time, that it is possible to produce LIG on certain woods under atmospheric conditions without additional fire protection treatment. We determined that the ability to produce LIG on untreated, natural wood under ambient atmosphere is favoured overall by a high density and a diffuse-porous xylem structure, as well as a high soluble lignin content. Some of these characteristics are similar to those required for high yields in char production. Problematic for the production of LIG-based electronics is the presence of pronounced growth rings, or other geometric wood features, with density variations, which can be reduced using specific cuts with minimized growth rings and absence of rays. This is the first time that untreated wood has been directly converted into LIG using a conventional CO2 laser and ambient atmosphere. Our results represent a further step towards the development of a new generation of sustainable electronics relying on natural materials.

Seeding Atomic Silver into Internal Lattice Sites of Transition Metal Oxide for Advanced Electrocatalysis.

Transition metal oxides (TMOs) are widely studied for loading of various catalysts due to their low cost and high structure flexibility. However, the prevailing close-packed nature of most TMOs crystals has restricted the available loading sites to surface only, while their internal bulk lattice remains unactuated due to the inaccessible narrow space that blocks out most key reactants and/or particulate catalysts. Herein, using tunnel-structured MnO2, this study demonstrates how TMO's internal lattice space can be activated as extra loading sites for atomic Ag in addition to the conventional surface-only loading, via which a dual-form Ag catalyst within MnO2 skeleton is established. In this design, not only faceted Ag nanoparticles are confined onto MnO2 surface by coherent lattice-sharing, Ag atomic strings are also seeded deep into the sub-nanoscale MnO2 tunnel lattice, enriching the catalytically active sites. Tested for electrochemical CO2 reduction reaction (eCO2RR), such dual-form catalyst exhibits a high Faradaic efficiency (94%), yield (67.3mol g-1 h-1) and durability (≈48h) for CO production, exceeding commercial Ag nanoparticles and most Ag-based electrocatalysts. Theoretical calculations further reveal the concurrent effect of such dual-form catalyst featuring facet-dependent eCO2RR for Ag nanoparticles and lattice-confined eCO2RR for Ag atomic strings, inspiring the future design of catalyst-substrate configuration.

Stabilization of antioxidant thyme-leaves extract (Thymus vulgaris) within biopolymers and its application in functional bread formulation

The aim of this study was to stabilize the antioxidant compounds of thyme (Thymus vulgaris) extract by spray-drying process and MD, WPC and MD-WPC carriers at different temperatures (120 and 150°С). Then, the optimal encapsulated sample was used in different ratios (1, 2, 3 and 5% w/w) to fortify pan-breads. The highest production yield (∼68 %) was obtained in the extract encapsulated with MD-WPC at 150°С. The values of moisture (3.2–4.1 %) and water activity (0.28–0.33) indicated the microbial stability of the powders. The functional characteristics of the particles (solubility and wettability) were affected by the composition and nature of the carriers. Also, the use of WPC led to an increase in physical stability, encapsulation efficiency (∼84 %), TPC (4.4 mgGAE/g) and antioxidant activity (∼77 %). The results of SEM and staining of the samples respectively indicated the effect of the process parameters on the morphology and the placement of the phenolic compounds within carrier's matrix. The physicochemical, textural characteristics, color indices (crumb and crust) and antioxidant activity of fortified breads were affected by the ratio of added free and spray-dried extract. The evaluation of sensory indices (color, texture, chewiness, taste and overall acceptance) indicated the ability to fortify bread with 3 % spray-dried extract.

Biodegradation Study of Styrene-Butadiene Composites with Incorporated Arthrospira platensis Biomass.

The preparation of polymer composites that incorporate material of a biogenic nature in the polymer matrices may lead to a reduction in fossil polymer consumption and a potentially higher biodegradability. Furthermore, microalgae biomass as biogenic filler has the advantage of fast growth and high tolerance to different types of culture media with higher production yields than those provided by the biomass of terrestrial crops. On the other hand, algal biomass can be a secondary product in wastewater treatment processes. For the present study, an SBS polymer composite (SBSC) containing 25% (w/w) copolymer SBS1 (linear copolymer: 30% styrene and 70% butadiene), 50% (w/w) copolymer SBS2 (linear copolymer: 40% styrene and 60% butadiene), and 25% (w/w) paraffin oil was prepared. Arthrospira platensis biomass (moisture content 6.0 ± 0.5%) was incorporated into the SBSC in 5, 10, 20, and 30% (w/w) ratios to obtain polymer composites with spirulina biomass. For the biodegradation studies, the ISO 14855-1:2012(E) standard was applied, with slight changes, as per the specificity of our experiments. The degradation of the studied materials was followed by quantitatively monitoring the CO2 resulting from the degradation process and captured by absorption in NaOH solution 0.5 mol/L. The structural and morphological changes induced by the industrial composting test on the materials were followed by physical-mechanical, FTIR, SEM, and DSC analysis. The obtained results were compared to create a picture of the material transformation during the composting period. Thus, the collected data indicate two biodegradation processes, of the polymer and the biomass, which take place at the same time at different rates, which influence each other. On the other hand, it is found that the material becomes less ordered, with a sponge-like morphology; the increase in the percentage of biomass leads to an advanced degree of degradation of the material. The FTIR analysis data suggest the possibility of the formation of peptide bonds between the aromatic nuclei in the styrene block and the molecular residues resulting from biomass biodegradation. It seems that in industrial composting conditions, the area of the polystyrene blocks from the SBS-based composite is preferentially transformed in the process.

ADM1-Based Modeling of Biohydrogen Production through Anaerobic Co-Digestion of Agro-Industrial Wastes in a Continuous-Flow Stirred-Tank Reactor System

Biological treatment is a promising alternative for waste management considering the environmentally sustainable concept that the European Union demands. In this direction, anaerobic digestion comprises a viable waste treatment process, producing high energy-carrier gases such as biomethane and biohydrogen under certain operating conditions. The mathematical modeling of this bioprocess can be used as a valuable tool for process scale-up with cost-effective implications. The scope of this work was the evaluation of the well-established Anaerobic Digestion Model 1 (ADM1) for use in two-stage anaerobic digestion of agro-industrial waste. Certain equations for the description of the metabolic pathways for lactate and bioethanol accumulation were implemented in the existing mechanistic model in order to enhance the model’s accuracy. The model presents a high estimation ability regarding the final product (H2 and biogas) reaching the same maximum value for the theoretical as the experimental data of these products (0.0012 and 0.0036 m3/d, respectively). The adapted ADM1 emerges as a useful instrument for designing anaerobic co-digestion processes with the goal of achieving high yields in fermentative hydrogen production, considering mixed biomass growth mechanisms.

Biosensor-assisted CRISPRi high-throughput screening to identify genetic targets in Zymomonas mobilis for high d-lactate production

Lactate is an important monomer for the synthesis of poly-lactate (PLA), which is a substitute for the petrochemical plastics. To achieve the goal of high lactate titer, rate, and yield for commercial production, efficient lactate production pathway is needed as well as genetic targets that affect high lactate production and tolerance. In this study, an LldR-based d-lactate biosensor with a broad dynamic range was first applied into Zymomonas mobilis to select mutant strains with strong GFP fluorescence, which could be the mutant strains with increased d-lactate production. Then, LldR-based d-lactate biosensor was combined with a genome-wide CRISPR interference (CRISPRi) library targeting the entire genome to generate thousands of mutants with gRNA targeting different genetic targets across the whole genome. Specifically, two mutant libraries were selected containing 105 and 104 mutants with different interference sites from two rounds of fluorescence-activated cell sorting (FACS), respectively. Two genetic targets of ZMO1323 and ZMO1530 were characterized and confirmed to be associated with the increased d-lactate production, further knockout of ZMO1323 and ZMO1530 resulted in a 15% and 21% increase of d-lactate production, respectively. This work thus not only established a high-throughput approach that combines genome-scale CRISPRi and biosensor-assisted screening to identify genetic targets associated with d-lactate production in Z. mobilis, but also provided a feasible high-throughput screening approach for rapid identification of genetic targets associated with strain performance for other industrial microorganisms.