Microalgae are rich in lipids, proteins, and exopolysaccharides, serving as potential producers of high-value by-products. Compared with monoculture, microalgal co-culture offers advantages such as fast growth rates and strong resistance, increasing the microalgal biomass and lipid production. Biomass production by microalgae co-culture is influenced by environmental conditions, nutrient composition, and external stress, and the produced biomass can be utilized for biofuel production and food processing. This article introduces the types of microalgal co-culture systems and reviews the related studies on the production of high-value by-products. It summarizes the factors influencing biomass production in microalgal co-culture systems and highlights the potential of microalgal co-culture for resource utilization. Furthermore, this article discusses the prospects and challenges of microalgal co-culture.

[Objective] We compared the microbial communities in the rhizosphere of plants with different genotypes and explored the relationship between microbial community and soil-borne disease occurrence, aiming to reveal the underlying mechanisms by which rhizosphere microorganisms assist plants in defending against pathogen invasion. [Methods] A pot experiment was conducted with the soil experiencing severe continuous cropping obstacles to compare the microbial communities in the rhizosphere of a susceptible watermelon variety 'zaojia 8424' and a resistant variety 'xinong 8' to Fusarium wilt. Furthermore, the relationship between microbial community and the occurrence of Fusarium wilt was explored. [Results] The resistant watermelon variety exhibited significantly lower disease index and pathogen (Fusarium oxysporum f. sp. niveum, FON) abundance than the susceptible watermelon variety. Although no significant difference was observed in the bacterial and fungal alpha diversity in the rhizosphere between resistant and susceptible varieties, the microbial beta diversity showcased significant difference between the two varieties. Moreover, both bacterial and fungal community composition was significantly correlated with pathogen abundance. Linear discriminant analysis effect size (LEfSe) further revealed that the resistant watermelon variety enriched more potential antagonistic or plant growth-promoting taxa represented by Actinobacteria and Rhizobiaceae in the rhizosphere. Interestingly, Fusarium was also enriched in the rhizosphere of the resistant variety, mainly composed of unclassified Fusarium and F. solani. Notably, the co-occurrence network of microorganisms in the rhizosphere of the resistant variety exhibited higher complexity and stability than that of the susceptible variety, with an increase of 18.18% in average degree and the nodes and edges dominated by Actinobacteria. [Conclusion] The watermelon varieties resistant and susceptible to Fusarium wilt demonstrate different microbial community composition in the rhizosphere. The enrichment of beneficial microbial taxa and interconnected co-occurrence network of the resistant variety contribute to plant defense against the pathogen invasion. This study disentangles the relationship between rhizosphere microbial community and soil-borne disease occurrence, providing important information and a theoretical basis for preventing and managing soil-borne diseases.

Electromagnetic radiation is a widespread physical phenomenon and exerts complex and profound effects on microorganisms. Understanding the state and function changes of microorganisms exposed to radiation is helpful to reveal the environmental response mechanisms of microorganisms and discover potential risk factors that threaten human health. By reviewing the relevant articles, we first discuss the damage of different types of electromagnetic radiation, including microwave, infrared, ultraviolet, X-rays, and γ-rays, to microorganisms. Furthermore, we elaborate on the molecular mechanisms by which electromagnetic radiation damages microorganisms from multi-omics. Finally, we reveal the potential relationship between the changes in the microbiome composition and the development of diseases in humans exposed to electromagnetic radiation.

[Objective] To study the inhibitory effect and mechanism of a novel antimicrobial peptide (BCE3) isolated from Penaeus vannamei processing waste fermented with Bacillus subtilis against Bacillus cereus. [Methods] The small peptide sequences in the fermentation broth were identified by ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS), and the potential antimicrobial peptides were screened by bioinformatics. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill curve of BCE3 against B. cereus were determined by the microdilution method and plate colony counting method. Then, the alkaline phosphatase release assay, propidium iodide (PI) staining, nucleic acid and protein leakage assays, and flow cytometry were employed to examine the effects of BCE3 on the cell wall and cell membrane of B. cereus. The effect of BCE3 on bacterial DNA was explored by the gel retardation assay, fluorescence spectroscopy, and molecular docking. Finally, the antimicrobial effects of BCE3 in rice were evaluated by the colony counting method. [Results] The potential antimicrobial peptide BCE3 screened out showed the MIC of 62.5 μg/mL and MBC of 125.0 μg/mL against B. cereus. The time-kill curve revealed that BCE3 reduced the bacterial count by 86.0% within 3 h (62.5 μg/mL), outperforming nisin. BCE3 caused damage to the bacterial cell wall and membrane, leading to the leakage of cell contents. Moreover, it can bind with DNA to kill the bacteria. In addition, BCE3 (125.0 μg/mL) exerted a significant inhibitory effect on the growth of B. cereus in rice. [Conclusion] BCE3 inhibits B. cereus by altering the permeability of the cell membrane and binding to DNA, thus leading to bacterial death. These findings provide a theoretical basis for application of BCE3 in the control of B. cereus.

[Objective] Microplastics (particle size < 5 mm) with hydrophobic surface, strong adsorption capacity, and difficult degradation can be retained in the environment for a long time and easily colonized by microorganisms, which poses a potential risk to the ecosystem. To study the distribution characteristics of microorganisms on the surface of microplastics in the wetland of Poyang Lake in wet and dry seasons. [Methods] Samples of water, sediments, and microplastics in sediments were collected from the wetland during the wet and dry seasons. The bacterial diversity and community structure in the samples were analyzed by high-throughput sequencing of the 16S rRNA gene. [Results] The richness and diversity of bacteria in the environment were higher than those on the microplastic surface in wet and dry seasons. During the wet season, the bacterial community structure was similar between the water and sediment samples and had large differences between the environment and the microplastic surface. During the dry season, the bacterial community structure was different among different samples. At the phylum level, the bacteria in the environment were dominated by Proteobacteria, Bacteroidetes, and Actinobacteria, while the bacteria on the microplastic surface during the wet season mainly included Proteobacteria, Bacteroidetes, and Firmicutes. The dominant bacterial phyla on the microplastic surface were similar to those in the environment during the dry season. The relative abundance of Pseudomonas on the microplastic surface was higher than that in the environment. Most of the keystone bacterial species in the wet and dry seasons belonged to Proteobacteria, including Sphingomonas. [Conclusion] This study reveals the differences in the bacterial community structure in the environment and on the microplastic surface in the Poyang Lake wetland in wet and dry seasons. The findings can enrich the knowledge about microplastics in lake wetlands in China and provide a theoretical basis for the management of lake environments including the Poyang Lake wetland.

[Objective] To use microorganisms to mobilize unavailable nutrients in soil for the utilization by leguminous crops and the sustainable and long-term utilization of soil resources. [Methods] Microbial culture and micro-plot experiments were carried out with Ceriporia lacerata HG2011, a new isolate of white-rot fungus, to investigate the fungal secretion, soil nitrogen (N) and phosphorus (P) mobilization, and influences on the nutrient uptake, growth, and yields of Vigna radiata and Vicia villosa. [Results] C. lacerata released cellulase, chitinase, β-l,3-glucanase, protease, phosphatase, and siderophore, and dissolved Ca₃(PO₄)₂ in pure culture. After being inoculated on the soil surface, this fungus formed colonies, with some mycelia extending into the soil, which decrease soil pH but increase the content of NH₄⁺-N, alkali-hydrolyzed N, water-soluble P and Olsen P, and the activities of protease and phosphatase. In general, C. lacerata inoculation improved soil N and P supplies, enhanced root activity, and promoted root growth, nodule formation and development, thus increasing the nutrient uptake, grain yield of V. radiata, and biomass of V. villosa. [Conclusion] C. lacerata dwelling in soil mobilized soil N and P to increase fertilizer use efficiency and promote crop growth. C. lacerata can be cultured with sawdust, straw, husk and other organic agricultural and forestry wastes, with low production costs. This study provides a new strategy for mobilizing soil nutrients, promoting the growth of leguminous crops such as V. radiata and V. villosa, and benefiting the conservation and sustainable use of cultivated lands.

Escherichia coli, a facultative anaerobic, flagellated, Gram-negative rod bacterium commonly parasitic in the intestines of humans and animals, is one of the common zoonotic pathogens. E. coli is easy to form biofilms, which are special aggregates formed by bacterial cells attached to each other and encased with self-produced extracellular matrix. Biofilm formation is a major reason for the difficulty in curing bacterial infectious diseases in clinical practice. It not only helps bacteria evade the host defense system but also reduces or prevents drugs from working, thereby inducing biofilm-associated infections (BAIs). This review introduces the molecular mechanism of E. coli biofilm formation from the perspective of the gene regulatory system and related regulatory proteins and summarizes the strategies for the prevention and treatment of BAIs, providing references for finding appropriate drug targets and preventing BAIs.

[Objective] To homologously overexpress an alkaline fungal laccase PIE5 (CcPIE5) in Coprinopsis cinerea FA2222 under the control of the Agaricus bisporus gpdII promoter. [Methods] The laccase activity reached (24.2±1.1) U/mL in the supernatant after 7 days of cultivation at 37 ℃ in the mKjalke medium. The purified CcPIE5 showcased the best performance at pH 8.0 and 60 ℃. [Results] Unlike other characterized fungal laccases, CcPIE5 was tolerant to high concentrations of NaCl. Particularly, both k_cat and K_m decreased when the concentration of NaCl was increased from 0 to 1.5 mol/L, which indicated that CcPIE5 demonstrated application potential in the dye decoloring of texile finishing. In dye decolorization, CcPIE5 efficiently degraded (92.9±2.3)% indigo carmine at pH 8.5 and 60 ℃, with syringic acid as the mediator. Isatin 5-sulfonic acid (ISA) was identified by LC-MS as the primary byproduct of indigo carmine degradation. [Conclusion] CcPIE5 is best-suited in decolorizing dyes under high temperatures and alkaline and salty conditions. It serves as a good candidate for specific applications in the environment and industry.

L-threonine is one of the eight essential amino acids that cannot be synthesized by the human body and must be taken from food. It is an important component of protein synthesis and is widely used in food, feed, medicine and other fields. At present, Escherichia coli can achieve a high threonine yield in fermentation, being the main bacterium used for industrial production of threonine. With the development of metabolic engineering, the modification of strains is no longer limited to mutagenesis, and the directed modification of strains greatly improves the production of L-threonine, facilitating the development of the L-threonine industry. This paper introduces the physicochemical properties and synthesis pathway of L-threonine and reviews the achievements in improving L-threonine production by metabolic engineering, aiming to enrich the knowledge about the modification of Escherichia coli for efficient synthesis of threonine.

β-glucosidases have been widely used in food, medicine, bioenergy and other fields, and thus it is necessary to explore new and efficient β-glucosidases.[Objective] To realize the prokaryotic expression of a GH1 glucosidase derived from Devosia psychrophila and characterize the enzymatic properties of the expressed protein. [Methods] The gene encoding the β-glucosidase derived from D. psychrophila was synthesized, named bgl59, and then transformed into Escherichia coli BL21(DE3). After the gene expression was induced, and the obtained protein was purified and characterized for the enzymatic properties. [Results] Bgl59 had a molecular weight of 48.8 kDa, with the highest activity at 55 ℃ and pH 6.0. After treatment for 1 h within the range of pH 5.0–8.5, Bgl59 maintained the relative activity over 80%. Bgl59 had the highest hydrolysis ability for 4-nitrophenyl-β-D-glucopyranoside (pNPG) among the eight substrates tested, with the K_m of 3.090 mmol/L, V_max of 194 μmol/(min·mg), and k_cat of 159 s⁻¹. The presence of 1 mmol/L of Ca²⁺ and Co²⁺ had a significant activating effect on Bgl59, while the presence of 0.1% SDS resulted in a complete loss of enzyme activity. The presence of 0.10 mol/L glucose and 0.30 mol/L xylose increased the activity of Bgl59 by 74% and 91%, respectively. Moreover, the enzyme remained the relative activity above 50% even when being cultured with 1.25 mol/L glucose or 2.00 mol/L xylose. [Conclusion] Bgl59 exhibits outstanding enzymatic properties, robust pH stability, and tolerance to metal ions and chemical reagents. It is a rare glucose-activated β-glucosidase with exceptional tolerance to glucose, holding significant potential for future industrial production and application.