Oddities and Curiosities in the Algal World

Advancements in sustainable production of biofuel by microalgae: Recent insights and future directions

Microalgae is considered as sustainable and viable feedstock for biofuel production due to its significant advantages over terrestrial plants. Algal biofuels have received significant attention among researchers and energy experts owing to an upsurge in global energy issues emanating from depletion in fossil fuel reserves increasing greenhouse gases emission conflict among agricultural crops, traditional biomass feedstock, and potential futuristic energy security. Further, the exploration of value-added microalgae as sustainable and viable feedstock for the production of variety of biofuels such as biogas, bio-hydrogen, bioethanol, and biodiesel are addressed. Moreover, the assessment of life-cycle, energy balance, and environmental impacts of biofuel production from microalgae are briefly discussed. The present study focused on recent advancements in synthetic biology, metabolic engineering tools, algal bio refinery, and the optimization of algae growth conditions. This paper also elucidates the function of microalgae as bio refineries, the conditions of algae-based cultures, and other operational factors that must be adjusted to produce biofuels that are price-competitive with fossil fuels.

Bioprospecting microalgae and cyanobacteria for biopharmaceutical applications

Microalgae and cyanobacteria have sparked a lot of interest due to their potential in various industries like biorefineries, biopharmaceuticals, food supplements, nutraceuticals, and other high-value products. Polysaccharides, vitamins, proteins, enzymes, and steroids are valuable products isolated from microalgae and cyanobacteria and potentially used in health and biomedical applications. Bioactive compounds derived from microalgae and cyanobacteria exhibit various pharmaceutical properties like antibacterial, anticancer, antiviral, antialgal, and antioxidant. From the properties listed above, the research for novel antibiotics has become particularly appropriate. In addition, the possible emergence of resistance against pathogens, as well as the potential decline in antibiotic efficacy, has prompted researchers to look for a new source of antibiotics. Microalgae and cyanobacteria have indicated a great and unexplored potential among these sources. For this reason, microalgae and cyanobacteria have been highlighted for their efficiency in different industrial sectors, as well as for their potential uses in the betterment of human and environmental health. This review gives an overview of bioactive compounds and metabolites with several biological properties isolated from microalgae and cyanobacteria for treating different animal and human diseases.

Bioactive peptides from microalgae: Focus on anti-cancer and immunomodulating activity

In addition to the rapidly expanding field of using microalgae for food and feed, microalgae represent a tremendous potential for new bioactive compounds with health-promoting effects. One field where new therapeutics is needed is cancer therapy. As cancer therapy often cause severe side effects and loose effect due to development of drug resistance, new therapeutic agents are needed. Treating cancer by modulating the immune response using peptides has led to unprecedented responses in patients. In this review, we want to elucidate the potential for microalgae as a source of new peptides for possible use in cancer management. Among the limited studies on anti-cancer effects of peptides, positive results were found in a total of six different forms of cancer. The majority of studies have been performed with different strains of Chlorella, but effects have also been found using peptides from other species. This is also the case for peptides with immunomodulating effects and peptides with other health-promoting effects (e.g., role in cardiovascular diseases). However, the active peptide sequence has been determined in only half of the studies. In many cases, the microalga strain and the cultivation conditions used for producing the algae have not been reported. The low number of species that have been explored, as opposed to the large number of species available, is a clear indication that the potential for new discoveries is large. Additionally, the availability and cost-effectiveness of microalgae make them attractive in the search for bioactive peptides to prevent cancer.

Algae-Based Biorefinery as a Sustainable Renewable Resource

Algae are a large and diverse group of autotrophic organisms that are multicellular and single-celled and found in a variety of environments. Biofuel production and value-added chemicals produced through a sustainable process are represented by the biorefinery of algae. Algae are important because of the production of polysaccharides, lipids, pigments, proteins, and other compounds for pharmaceutical and nutritional applications. They can also be used as raw materials for biofuel production. Moreover, they are useful for wastewater treatment. All these factors have absorbed the attentions of researchers around the world. This review focuses specifically on the potentials, properties, and applications of algae as a sustainable renewable resource, which can be a good alternative to other sources due to their high biomass production, less land required for cultivation, and the production of valuable metabolites.

Phytoremediation of 137Cs, 60Co, 241Am, and 239Pu from aquatic solutions using Chlamydomonas reinhardtii, Scenedesmus obliquus, and Chlorella vulgaris

Ecologically suitable methods for the decontamination of liquid radioactive waste or radioactively contaminated areas are becoming more and more important due to the pollution of the planet. We believe that phytoremediation of radionuclides using microalgae is one of the optimal ecological methods to decontamination of radioactive waste. Microalgae as unicellular organisms have a number of advantages over the other organisms used in bioremediation-high level of tolerance to the environment, fast growth rates, high tolerance to various pH levels, etc. In this study, we used 3 different strains of microalgae for phytoremediation of various radionuclides (¹³⁷Cs, ⁶⁰Co, ²⁴¹Am, and ²³⁹Pu). This research was focused on ex situ phytoremediation of radionuclides using microalgae at various pH levels of radioactively contaminated solutions. Due to the ability of microalgae to adapt to sometimes even extreme pH values, this research may be interesting for many institutions and researchers dealing with more environmentally friendly methods of decontamination of radioactive waste.

Sustainability and life cycle assessments of lignocellulosic and algal pretreatments

Bioenergy and Bioproducts have gained augmented relevance in the wake of depleting fossil fuels and escalating environmental problems induced by anthropogenic activities. The paper outlays the various applications of biomass and their significance in various processes. The prospects of lignocelluloses and algal raw materials to biofuel production are well established; however the life cycle analysis of every bioprocess becomes essential for its technical feasibility. The paper mainly targets the life cycle analysis of various pretreatment strategies adopted in the generation of biofuels. Biomass pretreatment- accounts to a major cost contributory factor in the entire production process and thus the identification of alternate cost effective strategies is of much significance. The LCA analysis identifies biofuel superior to petroleum chemicals based on its environmental effects, however better results are expected to be achieved by depending on methods using solar based energy sources for limiting fossil fuels even in processes of biofuel production.

Algae colonisation of brick pavement at the University of Venda: A potential slippery hazard

A brick pavement, tramped by humans, is exposed to atmospheric elements, thus allowing cyanobacteria and algae to colonise. In this article, we report on the factors that contribute to the slipperiness of a brick pavement at the University of Venda in the Limpopo province of the South Africa. Samples were collected from brick surfaces either colonised by green algae (treated) or not (control). The samples were acid-digested and analysed for metals by Inductively Coupled Plasma Mass Spectrometry (ICP MS) in parts per billion (ppb). The treated bricks, with green algae, had average high metal contents (ppb): Al 9456.02, Ti 731.23, V 46.44, Cr 78.85, Mn 862.93, Fe 16295.18, Co 23.57, Ni 59.36, Cu 66.31, Zn 160.57, As 7.92, Se 10.45, Mo 6.74, Cd 5.19, Sn 4.65, Sb 2.31 and Pb 19.51. In contrast, control bricks had a low average of metal content (ppb) as follows: Al 2.99, Ti 0.28, V 4.04, Cr 1.42, Mn 4.29, Fe 20.89, Co 0.36, Ni 2.74, Cu 5.64, Zn 4.21, As 0.56, Se <3.00, Mo 0.88, Cd 0.01, Sn 1.05, Sb 0.04 and Pb 0.04. Other factors that promote algae colonisation include high solar radiation, neutral pH, nutrients, low electrical conductivity and total dissolved solids. The algae colonisation of brick pavement results in an unaesthetic sighting and a slippery surface that is hazardous to humans.

Microbial Pigments in the Food Industry-Challenges and the Way Forward

Developing new colors for the food industry is challenging, as colorants need to be compatible with a food flavors, safety, and nutritional value, and which ultimately have a minimal impact on the price of the product. In addition, food colorants should preferably be natural rather than synthetic compounds. Micro-organisms already produce industrially useful natural colorants such as carotenoids and anthocyanins. Microbial food colorants can be produced at scale at relatively low costs. This review highlights the significance of color in the food industry, why there is a need to shift to natural food colors compared to synthetic ones and how using microbial pigments as food colorants, instead of colors from other natural sources, is a preferable option. We also summarize the microbial derived food colorants currently used and discuss their classification based on their chemical structure. Finally, we discuss the challenges faced by the use and development of food grade microbial pigments and how to deal with these challenges, using advanced techniques including metabolic engineering and nanotechnology.

The promising future of microalgae: current status, challenges, and optimization of a sustainable and renewable industry for biofuels, feed, and other products

Microalgae have recently attracted considerable interest worldwide, due to their extensive application potential in the renewable energy, biopharmaceutical, and nutraceutical industries. Microalgae are renewable, sustainable, and economical sources of biofuels, bioactive medicinal products, and food ingredients. Several microalgae species have been investigated for their potential as value-added products with remarkable pharmacological and biological qualities. As biofuels, they are a perfect substitute to liquid fossil fuels with respect to cost, renewability, and environmental concerns. Microalgae have a significant ability to convert atmospheric CO2 to useful products such as carbohydrates, lipids, and other bioactive metabolites. Although microalgae are feasible sources for bioenergy and biopharmaceuticals in general, some limitations and challenges remain, which must be overcome to upgrade the technology from pilot-phase to industrial level. The most challenging and crucial issues are enhancing microalgae growth rate and product synthesis, dewatering algae culture for biomass production, pretreating biomass, and optimizing the fermentation process in case of algal bioethanol production. The present review describes the advantages of microalgae for the production of biofuels and various bioactive compounds and discusses culturing parameters.

Potential for green microalgae to produce hydrogen, pharmaceuticals and other high value products in a combined process

Green microalgae for several decades have been produced for commercial exploitation, with applications ranging from health food for human consumption, aquaculture and animal feed, to coloring agents, cosmetics and others. Several products from green algae which are used today consist of secondary metabolites that can be extracted from the algal biomass. The best known examples are the carotenoids astaxanthin and β-carotene, which are used as coloring agents and for health-promoting purposes. Many species of green algae are able to produce valuable metabolites for different uses; examples are antioxidants, several different carotenoids, polyunsaturated fatty acids, vitamins, anticancer and antiviral drugs. In many cases, these substances are secondary metabolites that are produced when the algae are exposed to stress conditions linked to nutrient deprivation, light intensity, temperature, salinity and pH. In other cases, the metabolites have been detected in algae grown under optimal conditions, and little is known about optimization of the production of each product, or the effects of stress conditions on their production. Some green algae have shown the ability to produce significant amounts of hydrogen gas during sulfur deprivation, a process which is currently studied extensively worldwide. At the moment, the majority of research in this field has focused on the model organism, Chlamydomonas reinhardtii, but other species of green algae also have this ability. Currently there is little information available regarding the possibility for producing hydrogen and other valuable metabolites in the same process. This study aims to explore which stress conditions are known to induce the production of different valuable products in comparison to stress reactions leading to hydrogen production. Wild type species of green microalgae with known ability to produce high amounts of certain valuable metabolites are listed and linked to species with ability to produce hydrogen during general anaerobic conditions, and during sulfur deprivation. Species used today for commercial purposes are also described. This information is analyzed in order to form a basis for selection of wild type species for a future multi-step process, where hydrogen production from solar energy is combined with the production of valuable metabolites and other commercial uses of the algal biomass.