Toxin production in bloom-forming, harmful alga Alexandrium pacificum (Group IV) is regulated by cyst formation-promoting bacteria Jannaschia cystaugens NBRC 100362.

Harmful algal blooms (HABs) caused by dinoflagellates like Alexandrium pacificum pose significant ecological and public health risks due to their production of paralytic shellfish toxins (PSTs). Bacterial populations, particularly Alexandrium cyst formation-promoting bacteria (Alex-CFPB), are known to significantly influence growth, encystment, toxin synthesis, the composition of toxic components, and bloom dynamics of these dinoflagellates. However, the role of Alex-CFPB in Alexandrium toxin synthesis and the mechanisms thereof are still unclear.

The emerging potential of natural and synthetic algae-based microbiomes for heavy metal removal and recovery from wastewaters.

Heavy Metal (HM) bioremoval by microbes is a successful, environment-friendly technique, particularly at low concentrations of HMs. Studies using algae, bacteria, and fungi reveal promising capabilities in isolation and when used in consortia. Yet, few reviews have emphasized individual and collective HM removal rates and the associated mechanisms in natural or synthetic microbiomes.

Algal biopolymers as sustainable resources for a net-zero carbon bioeconomy.

The era for eco-friendly polymers was ushered by the marine plastic menace and with the discovery of emerging pollutants such as micro-, nano-plastics, and plastic leachates from fossil fuel-based polymers. This review investigates algae-derived natural, carbon neutral polysaccharides and polyesters, their structure, biosynthetic mechanisms, biopolymers and biocomposites production process, followed by biodegradability of the polymers. The review proposes acceleration of research in this promising area to address the need for eco-friendly polymers and to increase the cost-effectiveness of algal biorefineries by coupling biofuel, high-value products, and biopolymer production using waste and wastewater-grown algal biomass.

Dynamic Interactions between Autophagosomes and Lipid Droplets in .

Autophagy is a highly conserved catabolic process in eukaryotic cells by which waste cellular components are recycled to maintain growth in both favorable and stress conditions. Autophagy has been linked to lipid metabolism in microalgae; however, the mechanism underlying this interaction remains unclear. In this study, transgenic cells that stably express the red fluorescent protein (mCherry) tagged-ATG8 as an autophagy marker were established.

The Ancient Phosphatidylinositol 3-Kinase Signaling System Is a Master Regulator of Energy and Carbon Metabolism in Algae.

Algae undergo a complete metabolic transformation under stress by arresting cell growth, inducing autophagy and hyper-accumulating biofuel precursors such as triacylglycerols and starch. However, the regulatory mechanisms behind this stress-induced transformation are still unclear. Here, we use biochemical, mutational, and "omics" approaches to demonstrate that PI3K signaling mediates the homeostasis of energy molecules and influences carbon metabolism in algae.

Influence of Water Depth on Microalgal Production, Biomass Harvest, and Energy Consumption in High Rate Algal Pond Using Municipal Wastewater.

The high rate algal ponds (HRAP) powered and mixed by a paddlewheel have been widely used for over 50 years to culture microalgae for the production of various products. Since light incidence is limited to the surface, water depth can affect microalgal growth in HRAP. To investigate the effect of water depth on microalgal growth, a mixed microalgal culture constituting three major strains of microalgae including sp.

Microalgal diversity fosters stable biomass productivity in open ponds treating wastewater.

It is established that biodiversity determines productivity of natural ecosystems globally. We have proved that abiotic factors influenced biomass productivity in engineered ecosystems i.e.

Algae-bacteria interactions: Evolution, ecology and emerging applications.

Algae and bacteria have coexisted ever since the early stages of evolution. This coevolution has revolutionized life on earth in many aspects. Algae and bacteria together influence ecosystems as varied as deep seas to lichens and represent all conceivable modes of interactions - from mutualism to parasitism.

Enhancing microalgal biomass productivity by engineering a microalgal-bacterial community.

This study demonstrates that ecologically engineered bacterial consortium could enhance microalgal biomass and lipid productivities through carbon exchange. Phycosphere bacterial diversity analysis in xenic Chlorella vulgaris (XCV) confirmed the presence of growth enhancing and inhibiting microorganisms. Co-cultivation of axenic C.

A cost analysis of microalgal biomass and biodiesel production in open raceways treating municipal wastewater and under optimum light wavelength.

Open raceway ponds are cost-efficient for mass cultivation of microalgae compared with photobioreactors. Although low-cost options like wastewater as nutrient source is studied to overcome the commercialization threshold for biodiesel production from microalgae, a cost analysis on the use of wastewater and other incremental increases in productivity has not been elucidated. We determined the effect of using wastewater and wavelength filters on microalgal productivity.

Nutrient removal and biofuel production in high rate algal pond using real municipal wastewater.

This study evaluated the growth and nutrient removal ability of an indigenous algal consortium on real untreated municipal wastewater in a high rate algal pond (HRAP). The HRAP was operated semicontinuously under different hydraulic retention times (HRT: 2, 4, 6, and 8 days). The average removal efficiencies of chemical oxygen demand, and total nitrogen and phosphate of real municipal wastewater were maintained at 85.

Novel approach for the development of axenic microalgal cultures from environmental samples.

We demonstrated a comprehensive approach for development of axenic cultures of microalgae from environmental samples. A combination of ultrasonication, fluorescence-activated cell sorting (FACS), and micropicking was used to isolate axenic cultures of Chlorella vulgaris Beyerinck (Beijerinck) and Chlorella sorokiniana Shihira & R.W.

Microalgae-associated bacteria play a key role in the flocculation of Chlorella vulgaris.

Flocculation is most preferred method for harvesting microalgae, however, the role of bacteria in microalgal flocculation process is still unknown. This study proves that bacteria play a profound role in flocculating by increasing the floc size resulting in sedimentation of microalgae. A flocculating activity of 94% was achieved with xenic Chlorella vulgaris culture as compared to 2% achieved with axenic culture.

Lipid droplet synthesis is limited by acetate availability in starchless mutant of Chlamydomonas reinhardtii.

Phenotypic and genotypic changes in Chlamydomonas reinhardtii BafJ5, a starchless mutant, with respect to lipid metabolism was studied in different trophic states under nitrogen (N) sufficient and limited conditions. Interestingly, cellular lipid content increased linearly with input acetate concentration with highest lipid content (∼42%) under nitrogen limitation and mixotrophic state. RT-qPCR studies indicate that key fatty acid biosynthesis genes are down-regulated under N limitation but not under mixotrophic state, whereas, ACS2, encoding Acetyl-CoA synthetase, and DGTT4, encoding Diacylglycerol O-acyltransferase, are up-regulated under all conditions.

Simple, rapid and cost-effective method for high quality nucleic acids extraction from different strains of Botryococcus braunii.

This study deals with an effective nucleic acids extraction method from various strains of Botryococcus braunii which possesses an extensive extracellular matrix. A method combining freeze/thaw and bead-beating with heterogeneous diameter of silica/zirconia beads was optimized to isolate DNA and RNA from microalgae, especially from B. braunii.

Bio-mitigation of CO(2), calcite formation and simultaneous biodiesel precursors production using Chlorella sp.

In this study, an attempt was made to use micro-algal system for the production of biodiesel precursors and simultaneous CO(2) mitigation. Chlorella sp. was found to have a higher growth rate as compared to the other algal species tested namely Chlamydomonas sp.

Enhanced algal CO(2) sequestration through calcite deposition by Chlorella sp. and Spirulina platensis in a mini-raceway pond.

Biological CO(2) sequestration using algal reactors is one of the most promising and environmentally benign technologies to sequester CO(2). This research study was taken up to alleviate certain limitations associated with the technology such as low CO(2) sequestration efficiency and low biomass yields. The study demonstrates an increase in CO(2) sequestration efficiency by maneuvering chemically aided biological sequestration of CO(2).