Combined effects of LED lights and chicken manure on Neochloris oleoabundans growth

Lactic whey as a potential feedstock for exopolysaccharide production by microalgae strain Neochloris oleoabundans UTEX 1185

BACKGROUND

Lactic whey, a significant agro-industrial byproduct, poses environmental risks due to its chemical composition. Despite various valorization efforts, effective utilization remains a challenge. This study explores the potential of Neochloris oleoabundans, a microalgae known for its metabolic versatility and resilience to adverse conditions, to produce exopolysaccharides (EPS) using lactic whey as a substrate. We compared EPS production from lactose, the primary sugar in whey, with whole lactic whey. Characterization of the EPS was performed using Fourier transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry (GC-MS), while morphological analysis was conducted via scanning electron microscopy (SEM). This research aims to assess the feasibility of converting lactic whey into valuable EPS, providing a sustainable approach to managing this agro-industrial waste.

RESULTS

Lactic whey has produced the highest EPS and the FT-IR spectra revealed structural variations in the monomers which compose these polymers. Galactose and glucose were shown to be the primary monomers, according to GC-MS EPS analysis. SEM revealed a homogenous matrix and N. oleoabundans's bioflocculant characteristics.

CONCLUSIONS

Microalgae N. oleoabundans can produce EPS using lactic whey as feedstock and it has the potential to be employed as a wastewater treatment.

Bioenergy, Biofuels, Lipids and Pigments—Research Trends in the Use of Microalgae Grown in Photobioreactors

This scientometric review and bibliometric analysis aimed to characterize trends in scientific research related to algae, photobioreactors and astaxanthin. Scientific articles published between 1995 and 2020 in the Web of Science and Scopus bibliographic databases were analyzed. The article presents the number of scientific articles in particular years and according to the publication type (e.g., articles, reviews and books). The most productive authors were selected in terms of the number of publications, the number of citations, the impact factor, affiliated research units and individual countries. Based on the number of keyword occurrences and a content analysis of 367 publications, seven leading areas of scientific interest (clusters) were identified: (1) techno-economic profitability of biofuels, bioenergy and pigment production in microalgae biorefineries, (2) the impact of the construction of photobioreactors and process parameters on the efficiency of microalgae cultivation, (3) strategies for increasing the amount of obtained lipids and obtaining biodiesel in Chlorella microalgae cultivation, (4) the production of astaxanthin on an industrial scale using Haematococcus microalgae, (5) the productivity of biomass and the use of alternative carbon sources in microalgae culture, (6) the effect of light and carbon dioxide conversion on biomass yield and (7) heterotrophy. Analysis revealed that topics closely related to bioenergy production and biofuels played a dominant role in scientific research. This publication indicates the directions and topics for future scientific research that should be carried out to successfully implement economically viable technology based on microalgae on an industrial scale.

Microalgae-based livestock wastewater treatment (MbWT) as a circular bioeconomy approach: Enhancement of biomass productivity, pollutant removal and high-value compound production

The intensive livestock activities that are carried out worldwide to feed the growing human population have led to significant environmental problems, such as soil degradation, surface and groundwater pollution. Livestock wastewater (LW) contains high loads of organic matter, nitrogen (N) and phosphorus (P). These compounds can promote cultural eutrophication of water bodies and pose environmental and human hazards. Therefore, humanity faces an enormous challenge to adequately treat LW and avoid the overexploitation of natural resources. This can be accomplished through circular bioeconomy approaches, which aim to achieve sustainable production using biological resources, such as LW, as feedstock. Circular bioeconomy uses innovative processes to produce biomaterials and bioenergy, while lowering the consumption of virgin resources. Microalgae-based wastewater treatment (MbWT) has recently received special attention due to its low energy demand, the robust capacity of microalgae to grow under different environmental conditions and the possibility to recover and transform wastewater nutrients into highly valuable bioactive compounds. Some of the high-value products that may be obtained through MbWT are biomass and pigments for human food and animal feed, nutraceuticals, biofuels, polyunsaturated fatty acids, carotenoids, phycobiliproteins and fertilizers. This article reviews recent advances in MbWT of LW (including swine, cattle and poultry wastewater). Additionally, the most significant factors affecting nutrient removal and biomass productivity in MbWT are addressed, including: (1) microbiological aspects, such as the microalgae strain used for MbWT and the interactions between microbial populations; (2) physical parameters, such as temperature, light intensity and photoperiods; and (3) chemical parameters, such as the C/N ratio, pH and the presence of inhibitory compounds. Finally, different strategies to enhance nutrient removal and biomass productivity, such as acclimation, UV mutagenesis and multiple microalgae culture stages (including monocultures and multicultures) are discussed.

Bioprocessing of cultivated Chlorella pyrenoidosa on poultry excreta leachate to enhance algal biomolecule profile for resource recovery

The aim of this work was to study the cultivation of Chlorella pyrenoidosa on poultry excreta leachate to enhance the biochemical composition of algal biomass. The growth of microalgae was analyzed with different concentrations of poultry excreta leachate in BG-11 and distilled water. The biomolecules observed have high value in the form of carbohydrates (0.64 gL^-1), protein (1.02 gL^-1), chlorophyll (20 µg mL^-1) and lipid amount (0.49 gL^-1) with PEL _BG -25%. Biomass produced in PEL _BG -25% was also found to be 60% (2.5 gL^-1) higher than the BG-11 medium as a control (1.5gL^-1). Recovery of nutrients was observed with leachate wastewater concentration in terms of nitrate (84.2%), ammonium nitrogen (53.1%), and inorganic phosphate (96.2%). Hence, sustainability of microalgae cultivation in wastewater provides a new insight for resource utilization.