Omics approaches for microalgal applications: Prospects and challenges

Multi-omics approaches to improve malaria therapy

Malaria contributes to the most widespread infectious diseases worldwide. Even though current drugs are commercially available, the ever-increasing drug resistance problem by malaria parasites poses new challenges in malaria therapy. Hence, searching for efficient therapeutic strategies is of high priority in malaria control. In recent years, multi-omics technologies have been extensively applied to provide a more holistic view of functional principles and dynamics of biological mechanisms. We briefly review multi-omics technologies and focus on recent malaria progress conducted with the help of various omics methods. Then, we present up-to-date advances for multi-omics approaches in malaria. Next, we describe resistance phenomena to established antimalarial drugs and underlying mechanisms. Finally, we provide insight into novel multi-omics approaches, new drugs and vaccine developments and analyze current gaps in multi-omics research. Although multi-omics approaches have been successfully used in malaria studies, they are still limited. Many gaps need to be filled to bridge the gap between basic research and treatment of malaria patients. Multi-omics approaches will foster a better understanding of the molecular mechanisms of Plasmodium that are essential for the development of novel drugs and vaccines to fight this disastrous disease.

A Systemic Review on Microalgal Peptides: Bioprocess and Sustainable Applications

Nowadays, microalgal research is predominantly centered on an industrial scale. In general, multipotent bioactive peptides are the advantages over focal points over utilitarian nourishment as well as nutraceuticals. Microalgal peptides are now profoundly connected with biological properties rather than nutritive. Numerous techniques are employed to purify active peptides from algal protein using enzymatic hydrolysis; it is broadly used for numerous favorable circumstances. There is a chance to utilize microalgal peptides for human well-being as nutritive enhancements. This exhaustive survey details the utilization of microalgal peptides as antioxidant, anti-cancerous, anti-hypersensitive, anti-atherosclerotic, and nutritional functional foods. It is also exploring the novel technologies for the production of active peptides, for instance, the use of algal peptides as food for human health discovered restrictions, where peptides are sensitive to hydrolysis protease degradation. This review emphasizes the issue of active peptides in gastrointestinal transit, which has to be solved in the future, and prompt impacts.

Mechanisms for the stimulatory effects of a five-component mixture of antibiotics in Microcystis aeruginosa at transcriptomic and proteomic levels

Antibiotic contaminants could promote the formation of harmful cyanobacterial blooms through hormetic stimulation, but the mechanisms underlying these stimulatory effects remain unclear. This study investigated the biochemical, transcriptomic, and proteomic responses of a dominant bloom-forming cyanobacterium, Microcystis aeruginosa, to a five-component mixture of frequently detected antibiotics at current contamination levels. The growth rate of M. aeruginosa presented a U-shaped dose-response to 50-500 ng L^-1 of mixed antibiotics. Alterations in the transcriptome of M. aeruginosa suggested the excitation of both photosynthesis and carbon metabolism, increasing energy generation in response to oxidative stress induced by low-dose antibiotics, and thus contributing to the significant (p < 0.05) increase in growth rate, F_v/F_m, and cell density. Comparison between transcriptomic and proteomic responses further confirmed the action mode of the mixed antibiotics. Proteins and their corresponding genes related to ROS scavenging, photosynthesis, carbon fixation, electron transport, oxidative phosphorylation, and biosynthesis, showed consistent expression tendencies in response to 200 ng L^-1 of mixed antibiotics, which were credible action targets of mixed antibiotics in M. aeruginosa. Mixed antibiotics stimulated microcystin synthesis by upregulating a microcystin synthetase and its encoding gene (mcyC), which could increase the hazard of M. aeruginosa in aquatic environments.

Diatoms recovery from wastewater: Overview from an ecological and economic perspective

Alarming water pollution is toxic to the aquatic ecosystem leading to a sharp decline in species diversity. Diatoms have great potency to survive in contaminated water bodies, hence they can be compelling bioindicators to monitor the change in the environmental matrices effectively. Around the globe, researchers are intended to evaluate the impact of pollution on the diatoms recovery and techniques used for the assessment. The diatoms are precious for futuristic need viz. value-added products, energy generation, pharmaceuticals, and aquaculture feedstocks. All these applications led to a significant rise in diatoms research among the scientific community. This review presents different isolation practices, cultivation, and other challenges associated with the diatoms. A precise focus is given to diatoms isolation techniques from highly polluted water bodies with the main thrust towards obtaining an axenic culture to elucidate the significance of pure diatom cultures. Recovery of "jewels of the sea" from polluted water signifies the prospective ecological and economic aspects.

Metal ion removal using waste byssus from aquaculture

Byssus is a thread-like seafood waste that has a natural high efficiency in anchoring many metal ions thanks to its richness of diverse functional groups. It also has structural stability in extreme chemical, physical and mechanical conditions. The combination of these properties, absent in other waste materials, has novelty suggested its use as matrix for water remediation. Thus, pristine byssus, upon de-metalation, was studied to remove metal ions from ideal solutions at pH 4 and 7, as model chemical systems of industrial and environmental polluted waters, respectively. The byssus matrix's uptake of metal ions was determined by ICP-OES and its surface microstructure investigated by SEM. The results showed that the byssus matrix excellently uptakes metal ions slightly reorganizing its surface micro-structure. As example of its efficiency: 50 mg of byssus absorbed 21.7 mg·g-1 of Cd2+ from a 10 mM solution at pH 7. The adsorption isotherm models of Freundlich and Langmuir were mainly used to describe the system at pH 7 and pH 4, respectively. In conclusion, we showed that the byssus, a waste material that is an environmental issue, has the potential to purify polluted industrial and environmental waters from metal ions.

Prediction the performance of multistage moving bed biological process using artificial neural network (ANN)

Complexity, uncertainty, and high dynamic nature of nutrient removal through biological processes (BPs) makes it difficult to model and control these processes, forcing designers to rely on approximations, probabilities, and assumptions. To cope with this difficult task and perform an effective and well-controlled BP operation, an artificial neural network (ANN) algorithm was developed to simulate, model, and control a three-stage (anaerobic/anoxic and MBBR) enhanced nutrient removal biological process (ENR-BP) challenging real wastewater. The effect of surface area loading rate (SALR), organic matters (OMs), nutrients (N & P), feed flow rate (Q_feed), hydraulic retention time (HRT), and internal recycle flow (IRF) on the performance of the ENR-BP to fulfil rigorous discharge limitations were evaluated. Experimental data was used to develop the appropriate architecture for the AAN using iterative steps of training and testing. Significant removals of chemical oxygen demand (COD) (89.2 to 98.3%), NH₄⁺ (88.5 to 98.9%), and total phosphorus (TP) (77.9 to 99.9%) were achieved at a total HRT of 13.3 h (HRT_Z-1 = 3 h, HRT_Z-2 = 6 h and HRT_Z-3 = 5.3 h) and an IRF value of 1.75. The ENR-BP treatment mechanism relies on the use of OMs as a source of energy for phosphorus bio-uptake and the simultaneous nitrification and denitrification (SND) of nitrogen compounds. The removal efficiencies in the proposed ENR-BP were four fold higher than the suspended growth process and in the same order of magnitude of 5-stage Bardenpho-MBBR. The developed ANN-based model provides an efficient and robust tool for predicting and forecasting the performance of the ENR-BP.

Proteomic Profiling of Emiliania huxleyi Using a Three-Dimensional Separation Method Combined with Tandem Mass Spectrometry

Emiliania huxleyi is one of the most abundant marine planktons, and it has a crucial feature in the carbon cycle. However, proteomic analyses of Emiliania huxleyi have not been done extensively. In this study, a three-dimensional liquid chromatography (3D-LC) system consisting of strong cation exchange, high- and low-pH reversed-phase liquid chromatography was established for in-depth proteomic profiling of Emiliania huxleyi. From tryptic proteome digest, 70 fractions were generated and analyzed using liquid chromatography-tandem mass spectrometry. In total, more than 84,000 unique peptides and 10,000 proteins groups were identified with a false discovery rate of ≤0.01. The physicochemical properties of the identified peptides were evaluated. Using ClueGO, approximately 700 gene ontology terms and 15 pathways were defined from the identified protein groups with p-value ≤0.05, covering a wide range of biological processes, cellular components, and molecular functions. Many biological processes associated with CO₂ fixation, photosynthesis, biosynthesis, and metabolic process were identified. Various molecular functions relating to protein binding and enzyme activities were also found. The 3D-LC strategy is a powerful approach for comparative proteomic studies on Emiliania huxleyi to reveal changes in its protein level and related mechanism.

Deciphering the mechanism of carbon sources inhibiting recolorization in the removal of refractory dye: Based on an untargeted LC-MS metabolomics approach

In this study, the biological decolorization of reactive black 5 (RB5) by Klebsiella sp. KL-1 in yeast extract (YE) medium was captured the recolorization after exposure to O₂, which induced a 15.82% reduction in decolorization efficiency. Similar result was also observed in YE + lactose medium, but not in YE + glucose/xylose media (groups YE + Glu/Xyl). Through biodegradation studies, several degradation intermediates without quinoid structure were produced in groups YE + Glu/Xyl and differential degradation pathways were deduced in diverse groups. Metabolomics analysis revealed significant variations in up-/down-regulated metabolites using RB5 and different carbon sources. Moreover, the underlying mechanism of recolorization inhibition was proposed. Elevated reducing power associated with variable metabolites (2-hydroxyhexadecanoic acid, 9(R)-HODE cholesteryl ester, linoleamide, oleamide) rendered additional reductive cleavage of C-N bond on naphthalene ring. This study provided a new orientation to inhibit recolorization and deepened the understanding of the molecular mechanism of carbon sources inhibiting recolorization in the removal of refractory dyes.

High salinity acclimatization alleviated cadmium toxicity in Dunaliella salina: Transcriptomic and physiological evidence

In the present study, we tested the hypothesis that high salinity acclimatization can mitigate cadmium (Cd) toxicity in the microalga Dunaliella salina. To this end, microalgal cells were subjected to high salinity (60 g/L) for 12 weeks until the growth rate remained stable between generations and were then exposed to 2.5 mg/L of Cd for 4 days. Acute Cd toxicity impaired cell growth by increasing Cd bioaccumulation and lipid peroxidation, which reduced cellular pigment, total protein, and glutathione content. It also significantly weakened photosynthetic efficiency and total antioxidant capacity. However, acclimatization to high salinity alleviated these negative effects under Cd stress. To understand the potential mechanisms behind this phenomenon, 12 cDNA libraries from control, Cd-exposed (Cd), high salinity-acclimated (Salinity), and high salinity-acclimated with Cd exposure (Salinity + Cd) cells were derived using RNA sequencing. A total of 2019, 1799, 2150 and 1256 differentially expressed genes (DEGs) were identified from sample groups Salinity / Control, Cd / Control, Salinity + Cd / Control, and Salinity + Cd / Cd, respectively. Some of these DEGs were significantly enriched in ribosome, photosynthesis, stress defense, and photosynthesis-antenna proteins. Among these genes, 82 ribosomal genes were up-regulated in Salinity / Control (corrected P = 3.8 × 10^-28), while 81 were down-regulated in Cd / Control (corrected P = 1.1 × 10^-24). Moreover, high salinity acclimatization up-regulated 8 photosynthesis genes and 18 stress defense genes compared with the control. Additionally, 3 photosynthesis genes, 11 stress defense genes and 11 genes encoding light harvesting proteins were up-regulated by high salinity acclimatization under Cd exposure. Overall, high salinity acclimatization mitigated Cd toxicity, possibly by up-regulating the transcription of photosynthesis, stress defense, and ribosomal genes. These results provide new insights on cross-tolerance in microalgae.

Optimizing nutrient removal of moving bed biofilm reactor process using response surface methodology

The potential of 3-stages process (anaerobic, anoxic and moving bed biofilm reactor (MBBR)) for organic matter and nutrient removals from secondary WWTP effluents at various hydraulic retention time (HRT) and nitrate recycle ratio (R) was investigated. Percentage removals of total nitrogen (%TNremoval) and phosphorous (%TPremoval) were optimized using response surface methodology (RSM). Under optimized conditions (HRTtotal = 12.8 hr and R = 1.5) significant chemical oxygen demand removal (%CODremoval), %TNremoval and %TPremoval of 95.5%, 96.2%, 94.70% were attained. The MMBR effectively reduced organic matter and nutrient under low HRT and R. %TNremoval was improved by increasing the HRTR2 up to 1.5 h at R ≤ 2. Bio-uptake of phosphorus and nitrate is controlled by release of secondary phosphorous. Reactors demonstrated stable biofilm characteristics except for a slight decrease in biofilm thickness due to flow-shear stress. The 3-stages process performed four times higher than suspended growth process and similar to 5-stage Bardenpho-MBBR.

Genetic engineering of microalgae for enhanced biorefinery capabilities

Microalgae-based bioproducts are in limelight because of their promising future, novel characteristics, the current situation of population needs, and rising prices of rapidly depleting energy resources. Algae-based products are considered as clean sustainable energy and food resources. At present, they are not commercialized due to their high production cost and low yield. In recent years, novel genome editing tools like RNAi, ZNFs, TALENs, and CRISPR/Cas9 are used to enhance the quality and quantity of the desired products. Genetic and metabolic engineering are frequently applied because of their rapid and precise results than random mutagenesis. Omic approaches help enhance biorefinery capabilities and are now in the developing stage for algae. The future is very bright for transgenic algae with increased biomass yield, carbon dioxide uptake rate, accumulating high-value compounds, reduction in cultivation, and production costs, thus reaching the goal in the global algal market and capital flow. However, microalgae are primary producers and any harmful exposure to the wild strains can affect the entire ecosystem. Therefore, strict regulation and monitoring are required to assess the potential risks before introducing genetically modified microalgae into the natural ecosystem.

Microalgae with Immunomodulatory Activities

Microalgae are photosynthetic microorganisms adapted to live in very different environments and showing an enormous biochemical and genetic diversity, thus representing an excellent source of new natural products with possible applications in several biotechnological sectors. Microalgae-derived compounds have shown several properties, such as anticancer, antimicrobial, anti-inflammatory, and immunomodulatory. In the last decade, compounds stimulating the immune system, both innate immune response and adaptive immune response, have been used to prevent and fight various pathologies, including cancer (cancer immunotherapy). In this review we report the microalgae that have been shown to possess immunomodulatory properties, the cells and the cellular mediators involved in the mechanisms of action and the experimental models used to test immunostimulatory activities. We also report information on fractions or pure compounds from microalgae identified as having immunostimulatory activity. Given the increasing interest in microalgae as new eco-friendly source of bioactive compounds, we also discuss their possible role as source of new classes of promising drugs to treat human pathologies.

Chemometrics: a complementary tool to guide the isolation of pharmacologically active natural products

Chemometrics offers an important complementary tool to enhance the searching and isolation of bioactive natural products from natural sources.