Dye is an anionic common pollutant in industrial wastewater and poses a great threat to the environment and human health. Owing to its advantageous adsorption capacity, nanocellulose is widely used for wastewater treatment. The cell walls of Chlorella mainly comprise cellulose instead of lignin. In this study, residual Chlorella-based cellulose nanofiber (CNF) and cationic cellulose nanofiber (CCNF) with surface quaternization were prepared through homogenization. Moreover, Congo red (CR) was used as a model dye to measure the adsorption capacity of CNF and CCNF. The adsorption capacity was almost saturated when CNF and CCNF contacted CR for 100 min, and the adsorption kinetics coincided with the pseudo-secondary kinetics model. The initial concentration of CR considerably affected its adsorption on CNF and CCNF. Below the initial concentration of 40 mg/g, the adsorption on CNF and CCNF considerably increased with the increase in the initial concentration of CR. Based on the sorption isotherms analysis of CNF and CCNF, the Langmuir model fitted best with the experimental data. Thus, CNF and CCNF surfaces were uniform, and monolayer adsorption occurred. The adsorption of CR on CNF and CCNF was greatly affected by the pH value, and the acidic medium favored the adsorption of CR (especially for CCNF). CCNF showed a more advantageous adsorption capacity, with a maximum value of 1657.89 mg/g, compared to that of CNF (190.0 mg/g). According to the findings of this study, residual Chlorella-based CCNF could be a very promising adsorbent candidate for removing anionic dyes from wastewater.

Aronia melanocarpa is rich in anthocyanins, compounds with significant medicinal and industrial value, making it an attractive species for enhanced production. Compared with fruits or intact plants, callus tissue offers a uniform, controllable in vitro system that is particularly suitable for dissecting regulatory mechanisms under defined environmental conditions. Although light quality is known to influence anthocyanin biosynthesis, its specific regulatory mechanisms in A. melanocarpa remain unclear. In this study, callus tissues were cultured under six light regimes: full-spectrum LED, blue:red (5:1), red:blue (5:1), red:blue:white (1:1:1), red:white (5:1), and pure blue light. Anthocyanin content was quantified using the pH differential method, and the results showed that the blue:red (5:1) treatment produced the highest accumulation, reaching 14.06 mg/100 g. Transcriptome sequencing was then performed to compare the gene expression profiles between calli cultured under blue:red (5:1) light and those maintained in darkness. A total of 10,547 differentially expressed genes (DEGs) were identified, including 6134 upregulated and 4413 downregulated genes. Functional enrichment analysis indicated that these DEGs were mainly involved in anthocyanin biosynthesis and transport. Importantly, key structural genes such as PAL, C4H, 4CL, CHS, ANS, UFGT, and GST were significantly upregulated under blue:red (5:1) light, as further validated by qRT-PCR. Overall, our findings demonstrate that a blue:red (5:1) light ratio enhances anthocyanin accumulation by promoting the expression of biosynthetic and transport-related genes. This study not only provides new transcriptomic insights into the light-mediated regulation of secondary metabolism in A. melanocarpa callus, but also establishes a foundation for optimizing in vitro culture systems for sustainable anthocyanin production.

Lutein, a crucial carotenoid with diverse biological roles, is in high demand in the market. Current production predominantly relies on plant extraction, which is hindered by low yield and seasonal limitations. Microalgae, such as Chlorella and Chlamydomonas, known for their efficient lutein production due to high photosynthetic efficiency, rapid growth, and ease of cultivation, still require enhanced yields. This study presents a novel finding that co-cultivating A. protothecoides with S. liquefaciens significantly boosts lutein production. Optimization of carbon and nitrogen sources, nitrogen-to-phosphorus (N:P) ratio, and algal-bacterial inoculation ratio using BG11 medium was systematically conducted. The results indicate that supplementing with 3.0 g/L sodium acetate as the carbon source, 2.0 g/L sodium nitrate as the nitrogen source, sodium dihydrogen phosphate to achieve an N:P ratio of 12:1, and an algal:bacterial inoculation ratio of 10:1, resulted in an A. protothecoides biomass of 21.72 g/L (DWt) and a lutein yield significantly increased to 56.86 mg/g (DWt), a ninefold rise compared to monoculture. This co-cultivation approach offers a promising avenue for sustainable industrial lutein production.

In recent years, global warming caused by the greenhouse effect has become one of the greatest threats to mankind. This will have a serious impact on the environment and human body, such as land desertification, increase in ocean acidity, sea level rise, and increase in pests and diseases; affect peoples normal work and rest; and make people feel dizzy and nauseated. Excessive emissions of carbon dioxide (CO₂), the main component of the greenhouse gas, have contributed to the continued rise in Earths temperature. Although the world is vigorously developing clean energy to reduce carbon emissions, it will not replace fossil fuels in the short term. The conversion of biomass into energy is the most important way of energy utilization. Biomass energy refers to the solar energy stored in biomass in the form of chemical energy and is the fourth major energy source after oil, coal, and natural gas. At present, biofuels have gone through three developmental stages, which can be divided into first-generation biofuels, second-generation biofuels, and third-generation biofuels according to the types of raw materials and development history. The first generation of biofuels produced from food crops, such as bioethanol derived from sucrose and starch, has already entered the energy market. However, because the first generation of biofuels uses food crops as raw materials, there is a phenomenon of competing with people for food, and it is difficult to achieve large-scale application. To avoid the problem of food shortages, second-generation biofuels produced from nonfood crops, such as wood fiber, have been developed. Microalgae biomass energy is favored by governments and scholars all over the world because of its unique advantages of fast reproduction speed and high oil content. The cultivation of microalgae does not occupy traditional farmland, and the marginal land such as mountains, oceans, and deserts can cultivate microalgae, or develop microalgae cultivation in the air through the innovation of microalgae photosynthetic reactors. When municipal wastewater, food industry wastewater, and aquaculture wastewater are used as the medium for large-scale cultivation of microalgae, and waste gas from biogas power generation, flue gas from coal power plants, and industrial waste gas from fermentation are used as the CO₂ gas source for large-scale cultivation of microalgae, it can be further reduced. The comprehensive production cost of microalgae bioenergy plays a significant emission reduction effect. Combining the above advantages, the use of microalgae to produce first- or second-generation bioenergy has become a new research direction. This study focuses on the review of microalgal biomass in fuel, nonfuel, wastewater treatment, and fuel cell.

Selenium-enriched Dendrobium huoshanense C. Z. Tang et S. J. Cheng is a precious medicinal herb that combines traditional therapeutic value with modern nutritional benefits. However, its wild populations primarily inhabit special habitats like cliffs and rock crevices, resulting in limited yield and low selenium content. This study optimized an in vitro selenium-enriched cultivation system for D. huoshanense, investigating the regulatory mechanisms of selenium on physiological metabolism by modulating exogenous selenium concentrations, and determining the spatiotemporal distribution and speciation of selenium in plantlets. The results showed the optimal medium composition was as follows: MS + IBA (0.1 mg/L) + NAA (0.6 mg/L) + 7% agar + 30% sucrose + 100 g/L banana homogenate + 3 mg/L sodium selenite (pH 5.8). Under these conditions, roots served as the primary selenium accumulation sites at 30 and 60 days of cultivation. After 90 days, selenium redistribution occurred from storage organs (roots) to metabolically active organs (leaves). Organic selenium constituted 83.70% of total selenium, comprising 44.90% selenoproteins, 29.20% selenopolysaccharides, and 9.60% other organic forms. The contents of selenomethionine (SeMet), methylselenocysteine (MeSeCys), and selenocysteine (SeCys₂) were 0.63 ± 0.04, 0.20 ± 0.11, and 0.28 ± 0.06 mg/kg, respectively. Using plant tissue culture technology, we successfully cultivated selenium-enriched D. huoshanense, and investigated its growth metabolism, selenium translocation mechanisms, and selenium speciation. These findings provide theoretical foundations for developing selenium-enriched medicinal materials and have significant implications for enhancing the medicinal value of D. huoshanense.