Marine microalgae

Oceanic Breakthroughs: Marine-Derived Innovations in Vaccination, Therapy, and Immune Health

The vast, untapped potential of the world's oceans is revealing groundbreaking advancements in human health and vaccination. Microalgae such as Nannochloropsis spp. and Dunaliella salina are emerging as resources for recombinant vaccine development with specific and heterologous genetic tools used to boost production of functional recombinant antigens in Dunaliella salina and Nannochloropsis spp. to induce immunoprotection. In humans, several antigens produced in microalgae have shown potential in combating diseases caused by the human papillomavirus, human immunodeficiency virus, hepatitis B virus, influenza virus, Zika virus, Zaire Ebola virus, Plasmodium falciparum, and Staphylococcus aureus. For animals, microalgae-derived vaccine prototypes have been developed to fight against the foot-and-mouth disease virus, classical swine fever virus, vibriosis, white spot syndrome virus, and Histophilus somni. Marine organisms offer unique advantages, including the ability to express complex antigens and sustainable production. Additionally, the oceans provide an array of bioactive compounds that serve as therapeutics, potent adjuvants, delivery systems, and immunomodulatory agents. These innovations from the sea not only enhance vaccine efficacy but also contribute to broader immunological and general health. This review explores the transformative role of marine-derived substances in modern medicine, emphasizing their importance in the ongoing battle against infectious diseases.

Plastic pollution and degradation pathways: A review on the treatment technologies

In recent years, the production of plastic has been estimated to reach 300 million tonnes, and nearly the same amount has been dumped into the waters. This waste material causes long-term damage to the ecosystem, economic sectors, and aquatic environments. Fragmentation of plastics to microplastics has been detected in the world's oceans, which causes a serious global impact. It is found that most of this debris ends up in water environments. Hence, this research aims to review the microbial degradation of microplastic, especially in water bodies and coastal areas. Aerobic bacteria will oxidize and decompose the microplastic from this environment to produce nutrients. Furthermore, plants such as microalgae can employ this nutrient as an energy source, which is the byproduct of microplastic. This paper highlights the reduction of plastics in the environment, typically by ultraviolet reduction, mechanical abrasion processes, and utilization by microorganisms and microalgae. Further discussion on the utilization of microplastics in the current technologies comprised of mechanical, chemical, and biological methods focusing more on the microalgae and microbial pathways via fuel cells has been elaborated. It can be denoted in the fuel cell system, the microalgae are placed in the bio-cathode section, and the anode chamber consists of the colony of microorganisms. Hence, electric current from the fuel cell can be generated to produce clean energy. Thus, the investigation on the emerging technologies via fuel cell systems and the potential use of microplastic pollutants for consumption has been discussed in the paper. The biochemical changes of microplastic and the interaction of microalgae and bacteria towards the degradation pathways of microplastic are also being observed in this review.

Exploring contribution of phytoplankton cell death to settleable particulate organic carbon in the East China Sea in spring

Phytoplankton's death contributes to marine settleable particulate organic matter (POM). In this study, we used laboratory cultivation of different algal species to identify a positive correlation between the cumulative number of dead algal cells and POC>75 (carbon content of the settleable POM). The contribution coefficient of cell death to POC>75 varied among different algal species. Additionally, the field survey and incubation experiment were conducted in the East China Sea (ECS) to explore the spatial-temporal correlation between phytoplankton death and POC>75. The results concluded that phytoplankton death was the main factor controlling POC>75. In the ECS, the relationship between the surface cumulative mass of POC>75 and the cumulative number of dead cells followed: Cumulative mass of POC>75(mg) = 0.487 × Cumulative number of dead cells (/104) + 0.069. This study provided a methodology to quantitatively explain the relationship between phytoplankton death and settleable POM.

Does dinocyst wall composition really reflect trophic affinity? New evidence from ATR micro-FTIR spectroscopy measurements

Attenuated total reflection (ATR) microscope Fourier transform infrared (micro-FTIR) spectroscopy was used to investigate the dinosporin composition in the walls of modern, organic-walled dinoflagellate resting cysts (dinocysts). Variable cyst wall compositions were observed, which led to the erection of four spectrochemical groups, some with striking similarities to other resistant biomacromolecules such as sporopollenin and algaenan. Furthermore, possible proxies derivable from the spectrochemical composition of modern and fossil dinocysts were discussed. The color of the dinocyst walls was reflected in the spectral data. When comparing that color with a standard and the results of a series of bleaching experiments with oxidative agents, eumelanin was assigned as a likely pigment contributing to the observed color. Following this assignment, the role of eumelanin as an ultraviolet sunscreen in colored dinocysts was hypothesized, and its implications on the autofluorescence and morphological preservation of dinocysts were further discussed. Unlike what had previously been assumed, it was shown that micro-FTIR data from dinocysts cannot be used to unambiguously infer trophic affinities of their associated cells. Finally, using methods with high spatial resolutions (synchrotron transmission micro-FTIR and optical photothermal infrared spectroscopy), it was shown that dinocyst wall layers are chemically homogenous at the probed scales. This study fills a large knowledge gap in our understanding of the chemical nature of dinocyst walls and has nuanced certain assumptions and interpretations made in the past.

Adaptive responses of free-living and symbiotic microalgae to simulated future ocean conditions

Marine microalgae are a diverse group of microscopic eukaryotic and prokaryotic organisms capable of photosynthesis. They are important primary producers and carbon sinks but their physiology and persistence are severely affected by global climate change. Powerful experimental evolution technologies are being used to examine the potential of microalgae to respond adaptively to current and predicted future conditions, as well as to develop resources to facilitate species conservation and restoration of ecosystem functions. This review synthesizes findings and insights from experimental evolution studies of marine microalgae in response to elevated temperature and/or pCO₂ . Adaptation to these environmental conditions has been observed in many studies of marine dinoflagellates, diatoms and coccolithophores. An enhancement in traits such as growth and photo-physiological performance and an increase in upper thermal limit have been shown to be possible, although the extent and rate of change differ between microalgal taxa. Studies employing multiple monoclonal replicates showed variation in responses among replicates and revealed the stochasticity of mutations. The work to date is already providing valuable information on species' climate sensitivity or resilience to managers and policymakers but extrapolating these insights to ecosystem- and community-level impacts continues to be a challenge. We recommend future work should include in situ experiments, diurnal and seasonal fluctuations, multiple drivers and multiple starting genotypes. Fitness trade-offs, stable versus plastic responses and the genetic bases of the changes also need investigating, and the incorporation of genome resequencing into experimental designs will be invaluable.

Distribution and diversity of eukaryotic microalgae in Kuwait waters assessed using 18S rRNA gene sequencing

The microbial communities play a crucial role in ecosystem functioning through interactions among individuals and taxonomic groups in a highly dynamic marine ecosystem. The structure and functioning of the microbial communities are often influenced by the changes in the surrounding environment. Monitoring the microbial diversity of the marine ecosystem helps to understand spatial patterns of microbial community and changes due to season, climate, and various drivers of biological diversity. Kuwait is characterized by an arid environment with a high degree of temperature variation during summer and winter. Our understanding of spatial distribution patterns of microbial communities, their diversity, and the influence of human activities on the degree of changes in the diversity of the microbial community in Kuwait territorial waters remain unclear. In this study, we employed 18S rRNA sequencing to explore marine microalgal community composition and dynamics in seawater samples collected from Kuwait waters over two seasonal cycles across six locations. A total of 448,184 sequences across 36 replicates corresponding to 12 samples from six stations were obtained. The quality-filtered sequences were clustered into 1,293 representative sequences, which were then classified into different eukaryotic taxa. This study reveals that the phytoplankton community in Kuwait waters is diverse and shows significant variations among different taxa during summer and winter. Dinoflagellates and diatoms were the most abundant season-dependent microalgae taxa in Kuwait waters. Alexandrium and Pyrophacus were abundant in summer, whereas Gonyaulax was abundant during the winter. The abundance of Coscinodiscus and Navicula, of the diatom genera, were also dependent upon both seasonal and possible anthropogenic factors. Our results demonstrate the effectiveness of a sequencing-based approach, which could be used to improve the accuracy of quantitative eukaryotic microbial community profiles.

Protein Recovery from Underutilised Marine Bioresources for Product Development with Nutraceutical and Pharmaceutical Bioactivities

The global demand for dietary proteins and protein-derived products are projected to dramatically increase which cannot be met using traditional protein sources. Seafood processing by-products (SPBs) and microalgae are promising resources that can fill the demand gap for proteins and protein derivatives. Globally, 32 million tonnes of SPBs are estimated to be produced annually which represents an inexpensive resource for protein recovery while technical advantages in microalgal biomass production would yield secure protein supplies with minimal competition for arable land and freshwater resources. Moreover, these biomaterials are a rich source of proteins with high nutritional quality while protein hydrolysates and biopeptides derived from these marine proteins possess several useful bioactivities for commercial applications in multiple industries. Efficient utilisation of these marine biomaterials for protein recovery would not only supplement global demand and save natural bioresources but would also successfully address the financial and environmental burdens of biowaste, paving the way for greener production and a circular economy. This comprehensive review analyses the potential of using SPBs and microalgae for protein recovery and production critically assessing the feasibility of current and emerging technologies used for the process development. Nutritional quality, functionalities, and bioactivities of the extracted proteins and derived products together with their potential applications for commercial product development are also systematically summarised and discussed.

Production of sugars and levulinic acid from marine biomass Gelidium amansii

This study focused on optimization of reaction conditions for formation of sugars and levulinic acid from marine algal biomass Gelidium amansii using acid catalyst and by using statistical approach. By this approach, optimal conditions for production of sugars and levulinic acid were found as follows: glucose (reaction temperature of 139.4 degrees C, reaction time of 15.0 min, and catalyst concentration of 3.0%), galactose (108.2 degrees C, 45.0 min, and 3.0%), and levulinic acid (160.0 degrees C, 43.1 min, and 3.0%). While trying to optimize the conditions for the production of glucose and galactose, levulinic acid production was found to be minimum. Similarly, the production of glucose and galactose were found to be minimum while optimizing the conditions for the production of levulinic acid. In addition, optimized production of glucose required a higher reaction temperature and shorter reaction time than that of galactose. Levulinic acid was formed at a high reaction temperature, long reaction time, and high catalyst concentration. The combined results of this study may provide useful information to develop more economical and efficient systems for production of sugars and chemicals from marine biomass.