ABSTRACT
The natural environment is often contaminated with hydrophobic pollutants such as long-chain hydrocarbons, petrochemicals, oil spills, pesticides, and heavy metals. Hydrophobic pollutants with a toxic nature, slow degradation rates, and low solubility pose serious threats to the environment and human health. Decontamination based on conventional chemical surfactants has been found to be toxic, thereby limiting its application in pharmaceutical and cosmetic industries. In contrast, biosurfactants synthesized by various microbial species have been considered superior to chemical counterparts due to their non-toxic and economical nature. Some biosurfactants can withstand a wide range of fluctuations in temperature and pH. Recently, biosurfactants have emerged as innovative biomolecules not only for solubilization but also for the biodegradation of environmental pollutants such as heavy metals, pesticides, petroleum hydrocarbons, and oil spills. Biosurfactants have been well documented to function as emulsifiers, dispersion stabilizers, and wetting agents. The amphiphilic nature of biosurfactants has the potential to enhance the solubility of hydrophobic pollutants such as petroleum hydrocarbons and oil spills by reducing interfacial surface tension after distribution in two immiscible surfaces. However, the remediation of contaminants using biosurfactants is affected considerably by temperature, pH, media composition, stirring rate, and microorganisms selected for biosurfactant production. The present review has briefly discussed the current advancements in microbially synthesized biosurfactants, factors affecting production, and their application in the remediation of environmental contaminants of a hydrophobic nature. In addition, the latest aspect of the circular bioeconomy is discussed in terms of generating biosurfactants from waste and the global economic aspects of biosurfactant production.
ABSTRACT
In recent years, there has been a burgeoning interest in the utilization of cyanobacteria for the purpose of land rehabilitation via enhancements in soil fertility, prevent erosion, and counter desertification. This study evaluated the ability of Nostoc calcicola BOT1, Scytonema sp. BOT2, and their consortia to form biocrusts on the substrate of coarse sand, fine sand, and loamy soil. A nutrient- and water-deficient substrate was inoculated with cyanobacteria to facilitate biocrust formation and evaluate their impact on agriculture. Cyanobacteria inoculation resulted in significant improvements in soil fertility, especially in coarse and fine sand, which initially had the lowest fertility. The findings of this investigation underscore that the consortium of cyanobacteria exhibited greater efficacy than individual strains in enhancing soil fertility and stimulating plant growth. The loamy soil treated with the consortium had the highest plant growth across all soil types, in contrast to the individual strains. The consortium of cyanobacteria showed promising results in promoting biocrust formation and fostering rice seedling growth in fine sand. This study provides empirical evidence supporting the potential utility of cyanobacterial consortia as a valuable tool for the rehabilitation of degraded land. Furthermore, the results indicate that cyanobacterial species can persist in soil environments even following prolonged periods of desiccation.
ABSTRACT
In the recent past, various microalgae have been considered a renewable energy source for biofuel production, and their amount and extent can be enhanced by applying certain types of stress including salinity. Although microalgae growing under salinity stress result in a higher lipid content, they simultaneously reduce in growth and biomass output. To resolve this issue, the physiochemical changes in microalgae Scenedesmus sp. BHU1 have been assessed through two-stage cultivation. In stage-I, the maximum carbohydrate and lipid contents (39.55 and 34.10%) were found at a 0.4 M NaCl concentration, while in stage-II, the maximum carbohydrate and lipid contents (42.16 and 38.10%) were obtained in the 8-day-old culture. However, under increased salinity, Scenedesmus sp. BHU1 exhibited a decrease in photosynthetic attributes, including Chl-a, Chl-b, Fv/Fm, Y(II), Y(NPQ), NPQ, qP, qL, qN, and ETRmax but increased Y(NO) and carotenoids content. Apart from physiological attributes, osmoprotectants, stress biomarkers, and nonenzymatic antioxidants were also studied to elucidate the role of reactive oxygen species (ROS) facilitated lipid synthesis. Furthermore, elemental and mineral ion analysis of microalgal biomass was performed to evaluate the biomass quality for biofuel and cell homeostasis. Based on fluorometry analysis, we found the maximum neutral lipids in the 8-day-old grown culture at stage-II in Scenedesmus sp. BHU1. Furthermore, the use of Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy analyses confirmed the presence of higher levels of hydrocarbons and triacylglycerides (TAGs) composed of saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) in the 8-day-old culture. Therefore, Scenedesmus sp. BHU1 can be a promising microalga for potential biodiesel feedstock.
ABSTRACT
The global population growth has led to a higher demand for food production, necessitating improvements in agricultural productivity. However, abiotic and biotic stresses pose significant challenges, reducing crop yields and impacting economic and social welfare. Drought, in particular, severely constrains agriculture, resulting in unproductive soil, reduced farmland, and jeopardized food security. Recently, the role of cyanobacteria from soil biocrusts in rehabilitating degraded land has gained attention due to their ability to enhance soil fertility and prevent erosion. The present study focused on Nostoc calcicola BOT1, an aquatic, diazotrophic cyanobacterial strain collected from an agricultural field at Banaras Hindu University, Varanasi, India. The aim was to investigate the effects of different dehydration treatments, specifically air drying (AD) and desiccator drying (DD) at various time intervals, on the physicochemical properties of N. calcicola BOT1. The impact of dehydration was assessed by analyzing the photosynthetic efficiency, pigments, biomolecules (carbohydrates, lipids, proteins, osmoprotectants), stress biomarkers, and non-enzymatic antioxidants. Furthermore, an analysis of the metabolic profiles of 96-hour DD and control mats was conducted using UHPLC-HRMS. Notably, there was a significant decrease in amino acid levels, while phenolic content, fatty acids, and lipids increased. These changes in metabolic activity during dehydration highlighted the presence of metabolite pools that contribute to the physiological and biochemical adjustments of N. calcicola BOT1, mitigating the impact of dehydration to some extent. Overall, present study demonstrated the accumulation of biochemical and non-enzymatic antioxidants in dehydrated mats, which could be utilized to stabilize unfavorable environmental conditions. Additionally, the strain N. calcicola BOT1 holds promise as a biofertilizer for semi-arid regions.
ABSTRACT
In the present study, different microalgae were isolated from wastewater environment and evaluated for higher growth and lipid accumulation. The growth adaptability of all the isolated microalgae were tested for carbon source with supplementation of sodium bicarbonate in BG-11 N+ medium. Further based on the uptake rate of sodium bicarbonate and growth behavior, microalgal strains were selected for biofuel feedstock. During the study, growth parameters of all the isolates were screened after supplementation with various carbon sources, in which strain Scenedesmus sp. BHU1 was found highly effective among all. The efficacy of Scenedesmus sp. BHU1 strain under different sodium bicarbonate (4-20 mM) concentration, in which higher growth 1.4 times greater than control was observed at the concentration 12 mM sodium bicarbonate. In addition, total chlorophyll content (Chl-a + Chl-b), chlorophyll fluorescence (Fv/Fm, Y(II), ETR max, and NPQmax), and biomass productivity were found to be 11.514 µg/ml, 0.673, 0.675, and 31.167 µmol electrons m-2 s-1, 1.399, 59.167 mg/L/day, respectively, at the 12 mM sodium bicarbonate. However, under optimum sodium bicarbonate supplementation, 56.920% carbohydrate and 34.693% lipid content were accumulated, which showed potential of sodium bicarbonate supplementation in renewable biofuel feedstock by using Scenedesmus sp. BHU1 strain.
ABSTRACT
The world has faced the challenges of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) for the last two years, first diagnosed at the end of 2019 in Wuhan and widely distributed worldwide. As a result, the WHO has proclaimed the illness brought on by this virus to be a global pandemic. To combat COVID-19, researcher communities continuously develop and implement rapid diagnoses, safe and effective vaccinations and other alternative therapeutic procedures. However, synthetic drug-related side effects and high costs have piqued scientists' interest in natural product-based therapies and medicines. In this regard, antiviral substances derived from natural resources and some medicines have seen a boom in popularity. For instance, algae are a rich source of compounds such as lectins and sulfated polysaccharides, which have potent antiviral and immunity-boosting properties. Moreover, Algae-derived compounds or metabolites can be used as antibodies and vaccine raw materials against COVID-19. Furthermore, some algal species can boost immunity, reduce viral activity in humans and be recommended for usage as a COVID-19 preventative measure. However, this field of study is still in its early stages of development. Therefore, this review addresses critical characteristics of algal metabolites, their antioxidant potential and therapeutic potential in COVID-19.
ABSTRACT
Hyptis suaveolens is considered one of the most potent invaders in the eastern part of Uttar Pradesh, India. Climate change especially precipitation variability along with invasion has enormous consequences. To understand how an invasive plant (H. suaveolens) performs and interacts with precipitation variability, particularly in tropical monsoon climate, is vital. To assess the above, three rainout shelters with simulated rainfall of 1600 mm (60% more rainfall than ambient), 1100 mm (average rainfall) and 800 mm (20% less rainfall than ambient) along with one unsheltered plot (open C) were established. Three invaded grassland (IG) and three uninvaded grasslands (NIG) patches of 1 × 1 m2 size were established randomly in each sheltered and unsheltered plot. Among the studied physiological properties and growth measurements, photosynthetic rate, height, diameter and biomass varied significantly with precipitation, in general, the maximum value of these in plots receiving maximum precipitation. Also, the aboveground biomass of H. suaveolens was found to be more sensitive towards precipitation treatment than belowground biomass. H. suaveolens biomass was linearly related to soil moisture (R2 = 0.73), and a linear combination of SM and soil pH increased the R2 value by 19%. The results indicate that H. suaveolens mediates certain soil properties especially related to N-mineralisation, to maintain a constant supply of nutrient, for faster growth under the favourable condition of enhanced precipitation. These findings suggest that the population of H. suaveolens has not evolved drought tolerance, so it is likely that H. suaveolens will not spread in the part of the world which is drier either naturally or due to climate change.