Addition Of Microalgae Research Articles

Anaerobic co-digestion of cow manure and microalgae to increase biogas production: A sustainable bioenergy source

The biogas production from microalgae has gained attention due to fast depleting of fossil fuels and oil reserves. This study evaluated the anaerobic co-digestion of microalgae in various concentrations with cow manure to enhance biogas production. The biogas production of each experiment was measured using the water displacement method. The results indicated that the addition of microalgae significantly enhanced biogas production. Particularly, high methane yield of Anabaena sp. 50 %, Chlorella sp. 50 %, control was 345 ± 2.88 mL CH4/g VS, 297.96 ± 0.49 mL CH4/g VS, 138.32 ± 0.50 CH4/g VS respectively. The slurry produced by 50 % Anabaena sp. biogas plant exhibited the greatest level of seed germination. The current study demonstrated that Sorgham bicolor had the highest seed germination rate (94.2 %) root and shoot length of all crops. Therefore, it is possible to employ Anabaena sp. (50 %) and Chlorella sp. (50 %) in the rapid production of biogas. Moreover, agricultural output would be increased by using biogas slurry.

Algal-biochar and Chlorella vulgaris microalgae: a sustainable approach for textile wastewater treatment and biodiesel production

Microalgae technology is a viable solution for environmental conservation (carbon capture and wastewater treatment) and energy production. However, the nutrient cost, slow-kinetics, and low biosorption capacity of microalgae hindered its application. To overcome them, algal-biochar (BC) can be integrated with microalgae to treat textile wastewater (TWW) due to its low cost, its ability to rapidly adsorb pollutants, and its ability to serve as a nutrient source for microalgal-growth to capture CO2 and biodiesel production. Chlorella vulgaris (CV) and algal-BC were combined in this work to assess microalgal growth, carbon capture, TWW bioremediation, and biodiesel production. Results showed the highest optical density (3.70 ± 0.07 OD680), biomass productivity (42.31 ± 0.50 mg L−1 d−1), and dry weight biomass production (255.11 ± 6.01 mg L−1) in an integrated system of CV-BC-TWW by capturing atmospheric CO2 (77.57 ± 2.52 mg L−1 d−1). More than 99% bioremediation (removal of MB-pollutant, COD, nitrates, and phosphates) of TWW was achieved in CV-BC-TWW system due to biosorption and biodegradation processes. The addition of algal-BC and CV microalgae to TWW not only enhanced the algal growth but also increased the bioremediation of TWW and biodiesel content. The highest fatty acid methylesters (biodiesel) were also produced, up to 76.79 ± 2.01 mg g−1 from CV-BC-TWW cultivated-biomass. Biodiesel’s oxidative stability and low-temperature characteristics are enhanced by the presence of palmitoleic (C16:1) and linolenic (C18:3) acids. Hence, this study revealed that the integration of algal-biochar, as a biosorbent and source of nutrients, with living-microalgae offers an efficient, economical, and sustainable approach for microalgae growth, CO2 fixation, TWW treatment, and biodiesel production.Graphical

Effect of Macro and Microalgae Addition on Nutritional, Physicochemical, Sensorial, and Functional Properties of a Vegetable Cream.

Algae are a booming resource in the food industry due to their several health benefits. This study assesses the impact of the combined use of selected macro- and microalgae to improve the nutritional profile and the labeling of a vegetable cream by the introduction of nutrition and health claims. As macroalgae, two Ascophyllum nodosum L., one natural (An) and one smoked (AnS), were selected for their high iodine concentration and flavor notes. A new strain of Chlorella vulgaris, golden (CvG), was selected as the microalgae, which is rich in proteins and has a neutral sensorial profile (golden color and mild flavor). In this study, two vegetable creams were compared. The control (CTRL) versus one enriched with a mixture of macroalgae and microalgae (CV-AN). Sensory, physicochemical, and functional properties of both vegetable creams were evaluated. The bioactivity assessed was the effect of iodine as a health claim and antioxidant and antihypertensive properties. CV-AN vegetable cream showed significantly higher values (p < 0.05) for protein content, iodine value, and antioxidant activity, with no significant differences (p > 0.05) in antihypertensive activity or sensory panel. The incorporation of these algae resulted in a vegetable cream with a better nutritional profile and sensory acceptability comparable to the control, offering protein and iodine source claims in the labeling.

Effect of microalgae (Tetraselmis chui Butcher 1959) on growth and survival of nile tilapia (Oreochromis niloticus Linnaeus 1758) reared in low salinity biofloc system

Addition of microalgae in the biofloc system may improve growth and survival of Nile tilapia. Also, culturing Nile tilapia in saline water biofloc system may be an adaptation for freshwater shortage. In this study, the growth and survival of Nile tilapia cultured in a low salinity biofloc system with added microalgae was investigated. Increasing salinity in the culture system was done by gradually adding sea water into acclimatization container (618 L, v) on weekly basis for 4 weeks until 9 psu salinity was reached. Tilapia were allowed to adapt to salinity change for one week and fed with commercial feed twice a day until satiation. The biofloc experiment was conducted with 3 microalgal density treatments (5, 15 and 25 × 104 cells. mL-1) in triplicates. Average initial weight of experimental fish was 4.82 ± 0.76 g. Tilapia were reared for 40 days in aquaria (35 × 35 × 40 cm, l × w × h, 15 L, v) containing 8 individuals fish in each aquarium. The commercial pellets were delivered twice per day at 5% of tilapia biomass until satiation. T. chui was added to the tilapia culture every week. This study showed that the addition of microalgae did not affect the fish weight gain, specific growth rate and survival (p0.05). However, feed conversion ratio and culture productivity were better in tilapia supplied with weekly addition of T. chui at 15 × 104 cells mL-1 compared to other densities tested.Keywords:SalineBioflocMicroalgae

Hydrothermal co-liquefaction of microalgae, sugarcane bagasse, brewer's spent grain, and sludge from a paper recycling mill: Modeling and evaluation of biocrude and biochar yield

Biomass can be used as an energy source to thermochemical conversion processes to biocrude production. However, the supply and dependence on only one biomass for biocrude production can be an obstacle due to its seasonality, availability, and logistics costs. In this way, biomass waste and agroindustrial residues can be mixture and used as feedstock to the hydrothermal co-liquefaction (co-HTL) process as an alternative to obtaining biocrude. In this sense, the present paper analyzed the biocrude yield influence of the co-HTL from a quaternary unprecedented blend of different biomasses, such as sugarcane bagasse, brewer's spent grain (BSG), sludge from a paper recycling mill (PRM), and microalgae (Chlorella vulgaris). In this way, a simplex lattice design was employed and co-HTL experiments were carried out in a 2000 mL high-pressure stirred autoclave reactor under 275 °C for 60 min, considering 15% of feedstock/water ratio. Significant effects in each feedstock and their blends were analyzed aiming to increase biocrude and biochar yield. It was found that the addition of microalgae is only significant when considered more than 50% into the blend with BSG and PRM sludge to increase biocrude yield.

Multi-objective genetic algorithm approach for enhanced cumulative hydrogen and methane-rich syngas emission through co-pyrolysis of de-oiled microalgae and coal blending

Towards establishing low-carbon bio-economy, the energy-rich syngas is considered a global energy carrier. Targeting hydrogen as a promising advanced fuel, the significance of methane also increases due to its direct conversion capability into hydrogen. The current study aims to use a co-pyrolysis-based valorization of de-oiled microalgae and low-rank coal blend to generate H2 and CH4 rich syngas. Pyrolysis kinetic models, Kissinger-Akahira-Sunose (KAS) and Starink (STK) are used to evaluate apparent activation energy (Ea). The gradual addition of microalgae (0⎼100%) in coal reduces Ea from 189.11⎼55.87 kJ/mol and 180.16⎼54.61 kJ/mol by KAS and STK method, respectively. The maximum hymethane carrying ratio is observed 2.51 and 3.51 at optimized conditions of response surface methodology (RSM) and artificial neural network-based multi-objective genetic algorithm (ANN-MOGA), respectively. Maximum H2 (54.5 %) in the syngas is observed at mid pyrolysis stage (451 °C) using ANN-MOGA optimized conditions (blending ratio - 42.25 % and heating rate-13.8 °C/min). This study highlights the advantage of ANN-MOGA optimization over statistical based optimization. Hence, incorporating of the evolutionary algorithm as integrated ANN-MOGA optimization could be an efficient way for hymethane rich syngas emission in co-pyrolysis approach to gain carbon-neutral energy with zero waste discharge.

Photosynthetic nano fibers: Living microalgae packaging into polyvinyl alcohol nanofibers using an electrospinning method

AbstractAlthough microalgae are often studied for their biochemical extracts, utilizing them in a viable state opens new avenues for sustainable oxygenation in various systems. This study addresses the challenges of maintaining system homeostasis and presents an effective method for immobilizing live microalgae within poly(vinyl alcohol) (PVA) nanofibers using electrospinning technology. Characterization techniques, including scanning electron microscopy (SEM), fluorescence microscopy, Fourier‐transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC), were used to validate successful immobilization. Rheological studies were performed to investigate the influence of microalgae on the fiber morphology. Changing the PVA concentration, the fiber diameter could be regulated between 150 and 650 nm in the spinnable range. The addition of microalgae to the solution increased the viscosity of the prepared solution and reduced the resulting fiber diameter by approximately 2/3. Our results show that PVA nanofibers effectively encapsulate living microalgae and allow for sustained transport of nutrients and metabolites. The photosynthetic efficacy of the encapsulated microalgae was evaluated using dissolved oxygen measurements and showed two times higher rates of oxygen production and consumption compared with a film‐based approach. Our results show that PVA nanofibers effectively encapsulated living microalgae and allowed for the sustained transport of nutrients and metabolites. This innovative methodology provides a robust platform for immobilizing living microorganisms, with broad implications for applications ranging from regenerative medicine to sustainable agriculture.

Microalgae Inoculation Significantly Shapes the Structure, Alters the Assembly Process, and Enhances the Stability of Bacterial Communities in Shrimp-Rearing Water.

Intensive shrimp farming may lead to adverse environmental consequences due to discharged water effluent. Inoculation of microalgae can moderate the adverse effect of shrimp-farming water. However, how bacterial communities with different lifestyles (free-living (FL) and particle-attached (PA)) respond to microalgal inoculation is unclear. In the present study, we investigated the effects of two microalgae (Nannochloropsis oculata and Thalassiosira weissflogii) alone or in combination in regulating microbial communities in shrimp-farmed water and their potential applications. PERMANOVA revealed significant differences among treatments in terms of time and lifestyle. Community diversity analysis showed that PA bacteria responded more sensitively to different microalgal treatments than FL bacteria. Redundancy analysis (RDA) indicated that the bacterial community was majorly influenced by environmental factors, compared to microalgal direct influence. Moreover, the neutral model analysis and the average variation degree (AVD) index indicated that the addition of microalgae affected the bacterial community structure and stability during the stochastic process, and the PA bacterial community was the most stable with the addition of T. weissflogii. Therefore, the present study revealed the effects of microalgae and nutrient salts on bacterial communities in shrimp aquaculture water by adding microalgae to control the process of community change. This study is important for understanding the microbial community assembly and interpreting complex interactions among zoo-, phyto-, and bacterioplankton in shrimp aquaculture ecosystems. Additionally, these findings may contribute to the sustainable development of shrimp aquaculture and ecosystem conservation.

Evaluation of the Effect of Microalgae Chlorella vulgaris on the Performance of Membrane Bioreactor for Industrial Wastewater Treatment

Water pollution, especially from industry, is a problem that continues to emerge and even get worse. Rising sludge events often occur in industrial wastewater treatment processes. Process engineering with the addition of microalgae is proposed in this study to overcome the occurrence of rising sludge and improve wastewater quality based on dissolved oxygen levels. The control variables used were MLSS 1000 mg/L, microalgae Chlorella vulgaris 106 L, and urea and TSP 1,75 kg each. The dependent variable is rising sludge and DO levels while the independent variable is time. This research went through several stages, namely seeding microalgae, seeding microalgae into activated sludge in MBBR, experimenting with combining microalgae and activated sludge in MBBR, and installing ultrafiltration membranes with a WWTP capacity of 150 m3/day. The addition of microalgae in the MBBR process has a positive impact in improving the quality of industrial wastewater, which is characterized by the absence of rising sludge and DO levels exceeding the minimum threshold.

Modified glucose addition with microalgae can create a healthy and stable rearing microenvironment for Pacific white shrimp (Litopenaeus vannamei)

Carbon source addition is an effective microbial management strategy for healthy shrimp growth, but bottleneck problems have emerged in production applications. Beneficial microalgae with functions of capturing carbon dioxide, generating oxygen, absorbing phosphate and recruiting specific bacteria could theoretically modify carbon source addition. However, the implementation effectiveness and underlying microecological mechanism of the combined addition of carbon sources and microalgae remain unknown. Here, we investigated the effects of modified glucose addition with the microalga Nannochloropsis oculata on water quality, shrimp health and rearing water bacterial community. Although purification of the water environment was not achieved, the combined addition of glucose and microalgae significantly improved the shrimp survival rate and immune responses and altered the rearing water bacterial community structure. Network topology analysis indicated that the combined addition limited positive interactions and increased the modularity of the network, which enhanced the bacterial community stability. Partial least squares path modeling (PLS-PM) analysis showed that the bacterial community structure indirectly affected the survival rate of shrimp through bacterial network topological features. Furthermore, comparison of the biomarkers identified by shrimp survival rate-discriminatory importance and the bacterial taxa in the co-occurrence network module related to shrimp survival rate revealed that Rhodobacteraceae taxa recruited by the combined addition of glucose and microalgae might play important roles in maintaining healthy status of shrimp. These results provide a basis for developing novel microbial management strategies for sustainable aquaculture.

The Gill-Associated Bacterial Community Is More Affected by Exogenous Chlorella pyrenoidosa Addition than the Bacterial Communities of Water and Fish Gut in GIFT Tilapia (Oreochromis niloticus) Aquaculture System.

Microalgae has been widely used in aquaculture to improve both the water environment and fish growth; however, the current understanding of the effects of microalgae addition on the key players involved in regulating the water environment and fish health, such as microorganisms, remains limited. Here, a 50-day mesocosm experiment was set up to simulate the culture of Genetic Improvement of Farmed Tilapia (GIFT, Oreochromis niloticus) with an average weight of 14.18 ± 0.93 g and an average length of 82.77 ± 2.80 mm. Different amounts of Chlorella pyrenoidosa were added into these artificial systems to investigate dynamics of bacterial communities in aquaculture water, fish gill, and gut using amplicon-based high-throughput sequencing technology. Our results showed that Chlorella pyrenoidosa addition increased diversity and network complexity of gill-associated bacterial communities rather than those of the water and gut. Furthermore, more biomarkers in the gill-associated bacterial communities were detected in response to Chlorella pyrenoidosa addition than the water and fish gut samples. These findings highlighted the high sensitivity of gill-associated bacterial communities in response to the Chlorella pyrenoidosa addition, implying Chlorella pyrenoidosa addition could play important roles in regulating the fish mucosal immunity by altering the gill-associated microbiota.

Marine Microalgae as a Nutritive Tool to Mitigate Ruminal Greenhouse Gas Production: In Vitro Fermentation Characteristics of Fresh and Ensiled Maize (Zea mays L.) Forage.

The aim of the present study was to evaluate the effects of marine microalgae (Dunaliella salina) as a food additive on biogas (BG), methane (CH4), carbon monoxide (CO), and hydrogen sulfide (H2S) production kinetics, as well as in in vitro rumen fermentation and the CH4 conversion efficiency of different genotypes of maize (Zea mays L.) and states of forage. The treatments were characterized by the forage of five maize genotypes (Amarillo, Montesa, Olotillo, Tampiqueño, and Tuxpeño), two states of forage (fresh and ensiled), and the addition of 3% (on DM basis) of microalgae (with and without). The parameters (b = asymptotic production, c = production rate, and Lag = delay phase before gas production) of the production of BG, CH4, CO, and H2S showed an effect (p < 0.05) of the genotype, the state of the forage, the addition of the microalgae, or some of its interactions, except for the time in the CO delay phase (p > 0.05). Moreover, the addition of microalgae decreased (p < 0.05) the production of BG, CH4, and H2S in most of the genotypes and stages of the forage, but the production of CO increased (p < 0.05). In the case of fermentation characteristics, the microalgae increased (p < 0.05) the pH, DMD, SCFA, and ME in most genotypes and forage states. With the addition of the microalgae, the fresh forage from Olotillo obtained the highest pH (p < 0.05), and the ensiled from Amarillo, the highest (p < 0.05) DMD, SCFA, and ME. However, the ensiled forage produced more (p < 0.05) CH4 per unit of SFCA, ME, and OM, and the microalgae increased it (p < 0.05) even more, and the fresh forage from Amarillo presented the highest (p < 0.05) quantity of CH4 per unit of product. In conclusion, the D. salina microalga showed a potential to reduce the production of BG, CH4, and H2S in maize forage, but its effect depended on the chemical composition of the genotype and the state of the forage. Despite the above, the energy value of the forage (fresh and ensiled) improved, the DMD increased, and in some cases, SCFA and ME also increased, all without compromising CH4 conversion efficiency.

Improvement of biocorrosion resistance on steel using full annealing heat treatment

The performance of a material structure can be affected due to corrosion damage. Corrosion is a decrease in metal quality caused by electrochemical reactions between metals and their surrounding environment. One of the causes of corrosion is microalgae or called biocorrosion. Corrosion can cause failure of the pipe structure which causes the pipe to not operate properly. The purpose of the research was to determine the corrosion rate of ASTM A53 steel material with full annealing heat treatment and without heat treatment. Second research aim was to determine the biocorrosion with added of microalgae and without the addition of microalgae. Heat treatment and non-heat treatment materials were testing using the immersion corrosion test method, which was soaked in artificial seawater with a salinity of 35‰. Based on the results, the highest biocorrosion rate on non-heat treated materials with the addition of Chrorella vulgaris reached 0.2780 mpy. While the biocorrosion rate after full annealing treatment was 0.1434 mpy and the size of uniform corrosion and pitting decreased. The percentages reduction of biocorrosion rete was 46.58%. This indicates that the addition of Chlorella vulgaris can accelerate the corrosion rate and full annealing can inhibit the biocorrosion rate.

Effect of Type of Flour and Microalgae (Chlorella vulgaris) on the Rheological, Microstructural, Textural, and Sensory Properties of Vegan Muffins

The aim of this study was to develop a recipe for vegan muffins using wheat flour (100%) and a blend of whole-grain spelt flour (50%) and wheat flour (50%) enriched with microalgae (0, 0.5, 1.0, and 1.5% (g/100 g flour)). Replacing wheat flour with whole-grain spelt flour and adding microalgae while eliminating egg white from a recipe can affect the rheological properties of the dough and also the microstructure and texture of the muffins. The study analyzed the effects of the type of flour and the addition of microalgae on the rheological properties of the raw dough, measured through the oscillatory method, as well as the texture and microstructure, determined via X-ray microtomography. Additionally, the sensorial quality of the muffins was analyzed. The use of spelt flour in the formulation of muffins affected the rheological properties of the dough irrespective of the addition of microalgae. The dough made with spelt flour exhibited higher viscosity (consistency coefficient (K) was 74.7 Pa·sn), but it was more cohesive and less springy compared to the dough made with wheat flour alone, which had a K = 58.3 Pa·sn. Incorporating a mixture of spelt and wheat flour along with a 1.5% addition of microalgae made the dough more viscous (K = 118.6 Pa·sn), leading to a fine, porous microstructure (porosity was 69.7%) and a crumbly texture (hardness was 52.2 N) in the muffins. On the other hand, the wheat flour dough with 1.5% microalgae had a consistency coefficient of 69.3 Pa·sn, while the muffin porosity was 67.1% and the hardness 61.8 N. The microstructure had a strong effect on the texture of the muffin crumb. The new wheat flour products with microalgae exhibited a higher proportion of closed pores in their microstructure, whereas samples containing spelt flour and microalgae showed the opposite trend, with more open pores. The greatest difference in closed pores was observed with the addition of 1.5% of microalgae (33.4% in wheat muffins and 26.9% in spelled muffins). The presence of closed porosity contributed to the harder and less consistent texture observed in the muffins. However, despite the instrumental evaluation results, all the new products were accepted by consumers in terms of appearance, taste, and overall quality.

Protein Quality and Protein Digestibility of Vegetable Creams Reformulated with Microalgae Inclusion.

Microalgae are considered a valuable source of proteins that are used to enhance the nutritional value of foods. In this study, a standard vegetable cream recipe was reformulated through the addition of single-cell ingredients from Arthrospira platensis (spirulina), Chlorella vulgaris, Tetraselmis chui, or Nannochloropsis oceanica at two levels of addition (1.5% and 3.0%). The impact of microalgae species and an addition level on the amino acid profile and protein in vitro digestibility of the vegetable creams was investigated. The addition of microalgae to vegetable creams improved the protein content and the amino acid nutritional profile of vegetable creams, whereas no significant differences were observed in protein digestibility, regardless of the species and level of addition, indicating a similar degree of protein digestibility in microalgae species despite differences in their protein content and amino acid profile. This study indicates that the incorporation of microalgae is a feasible strategy to increase the protein content and nutritional quality of foods.

Hemato-immunological parameters can be influenced by microalgae addition and fish feed supplementation in the integrated rearing of Pacific white shrimp and juvenile Nile tilapia using biofloc technology

This study evaluated the effects of microalgae (Scenedesmus obliquus) addition and fish feed supplementation on hemato-immunological parameters of Pacific white shrimp (Penaeus vannamei) and juvenile Nile tilapia (Oreochromis niloticus) cultured in integration using biofloc technology for 62 days. The experiment was designed as a factorial design with two factors, totaling four experimental groups: (1) No addition of microalgae and no addition of fish feed; (2) no addition of microalgae and addition of fish feed; (3) addition of microalgae and no addition of fish feed; and (4) addition of microalgae and addition of fish feed. In all groups shrimp were fed according to a feeding table. Shrimp (2.16 ± 0.01 g) and fish (1.53 ± 0.12 g) were cultured under densities of 400 shrimp m−3 and 522 fish m−3 in 800 L and 90 L (useful volumes) tanks maintained under water recirculation. Microalgae was added two times a week for a final concentration of 5 mg L−1 in the units, while a commercial fish feed was provided at the rate of 1% of the fish biomass daily. At the end of the trial, the fish and shrimp were sampled for the hemato-immunological analyses. As regards the shrimp, there was a significant effect of the interaction on total hemocyte count (p < 0.05), in which the highest value occurred in the group with microalgae/no fish feed addition. There was also a significant effect of microalgae addition on serum protein (p < 0.05), with the highest values occurring in the treatments that employed microalgae. In the case of the fish, the monocyte count was significantly affected by the fish feed addition (p < 0.05), the highest values being observed when the feed was provided. There were also significant effects of the interaction and of microalgae addition on mean corpuscular volume and mean corpuscular hemoglobin concentration (p < 0.05), with the highest values occurring in the group that received microalgae but no fish feed and in the groups that did not receive microalgae, respectively. Overall, these results suggest an enhanced immunological status for the shrimp due to increases in total hemocyte count and high serum protein concentration when microalgae was added and an improved nutritional status for the fish that received feed due to increased circulating monocytes, along with possible greater erythrocyte stability when microalgae was added.

Optimizing engine performance and reducing emissions of greenhouse gases through spirulina microalgae and nano-additive blends

The shift in focus towards biofuels has led to the attention towards fourth-generation fuels, particularly microalgae, due to its high oil productivity and simple cultivation processes. The current study aimed to examine the effects of spirulina microalgae blends in a naturally aspirated diesel engine by testing two blend percentages (15% and 30%) and incorporating Fe2O3 nanoparticles (75 ppm). A series of test conducted in a single-cylinder engine with an optimum compression ratio of 17.5. The fuels tested include 100% diesel (D0), diesel with Fe2O3 nanoparticles (DF), diesel with 15% microalgae blends (B15), diesel with 15% microalgae blends and Fe2O3 nanoparticles (B15F), diesel with 30% microalgae blends (B30), and diesel with 30% microalgae blends and Fe2O3 nanoparticles (B30F). The results showed that the addition of microalgae blends led to a marginal increase in engine performance, while the addition of Fe2O3 nanoparticles led to a significant increase in brake thermal efficiency and decreased fuel consumption. The emissions rate was also lower compared to diesel, but the addition of Fe2O3 nanoparticles increased the oxygen content in the fuel, thereby improving the combustion rates. By ensuring the complete combustion the formation of CO2, HC and smoke intensity was also found to be significantly lower compared to diesel fuel. On the contrary, NOx increased due to the cylinder temperatures. This research highlights the potential of using microalgae as a sustainable source of biofuel, and the positive effects of adding Fe2O3 nanoparticles to enhance the fuel's efficiency.

Microalgae blending for sustainable metallurgical coke production – Impacts on coking behaviour and coke quality

The steel industry is responsible for approximately 7% of global greenhouse gas emissions, mainly in the form of CO2 from the blast furnace ironmaking process. Among several strategies proposed to reduce CO2 emission, the partial replacement of coal with biomass during the cokemaking process has gained increasing interest. However, such replacement with lignocellulosic biomass species demonstrates a detrimental effect on coke quality. In this work, as an alternative to lignocellulosic biomass, the use of microalgae biomass (Chlorella vulgaris) is discussed for coal blending and bio-coke production. Three Australian metallurgical coal samples, varying in rank and fluidity, were blended with microalgae at up to 10 wt% to evaluate the impact of biomass addition rate on coking behaviour and coke quality. The work evaluates the impact of microalgae on coal blend properties, coking performance, and coke quality and strength (CSR/CRI, microtexture, and coke reactivity). The results demonstrated that microalgae blending with high-rank premium metallurgical coals did not adversely affect thermoplastic properties during coking or resultant bio-coke quality. Furthermore, the reactivity under simulated blast furnace conditions showed that microalgae addition led to a slight increase of up to 4.4% in coke gasification reactivity, which was attributed to the higher alkali content and isotropic textures in coke. Unlike lignocellulosic biomass, in bio-cokes produced by blending microalgae no porous and fibrous structures related to the biochar structure were identified. It was postulated that this non-fibrous nature of microalgae allows cokes to maintain their strength even for blending up to 10 wt%.

White and honey Chlorella vulgaris: Sustainable ingredients with the potential to improve nutritional value of pork frankfurters without compromising quality

This study aimed to evaluate the effect of the chlorophyll-deficient microalgae mutants, honey (yellow) and white Chlorella vulgaris, (3%) on the nutritional, physicochemical, microbiological, and sensory characteristics of frankfurters. The presence of microalgae resulted in increased PUFA content and higher PUFA/SFA ratio, but lower n-6/n-3 ratio and lipid indices (P < 0.05). C. vulgaris inclusion in frankfurters increased (P < 0.05) Na, K, Ca, P, and Zn and improved the Na/K ratio, but lowered Mn, and in the case of white C. vulgaris, Cu content, compared to the control. The higher protein content decreased water release from emulsions elaborated with microalgae. White C. vulgaris inclusion decreased cohesiveness and springiness of the frankfurters. Due to the presence of pigment, microalgae inclusion led to a decrease in redness and an increase in yellowness of frankfurters. The presence of microalgae resulted in lower (P < 0.05) bacterial counts and did not affect TBARs during storage. The addition of microalgae in frankfurters produced acceptable sensory characteristics but resulted in lower scores compared to reference products.

Utilization of microalgae, Chlorella sp. UMT LF2 for bioremediation of Litopenaeus vannamei culture system and harvesting using bio-flocculant, Aspergillus niger

Microalgae are well known as autotrophic microorganisms in aquaculture wastewater treatment, however their role in the aquaculture system is rarely explored. The purpose of this study is to evaluate the influence of adding microalgae, Chlorella sp. UMT LF2, on the functionality for bioremediation and growth performance of Whiteleg shrimp, Litopenaeus vannamei in the nursery phase reared in a control culture system. Secondly, the response surface methodology (RSM) was used to investigate further on the optimal condition for the harvesting process of excess microalgae biomass using bio-flocculant from the filamentous fungus, Aspergillus niger. The experimental set-up with Chlorella sp. additions were compared to the control group without the microalgae addition based on the water quality, microalgae biomass and shrimp growth performance. Water samples were collected and underwent in-situ and ex-situ involving nine physicochemical parameters. The results showed that introducing microalgae with zero water exchange as treatment tanks reduced the NH3, NO2− and PO43− during the intermediate until the two days before the 30-day culture period's end. Microalgae also enhanced shrimp survival and growth performance significantly 89% as compared to the control, 68%. Furthermore, the culture with the addition of microalgae maintained pH stability and enhanced dissolved oxygen during daytime in the culture water. Therefore, this finding confirmed that Chlorella sp. UMT LF2 addition is promising in improving rearing environment and nursery performance for L. vannamei in culture system. However, further research is required to demonstrate the harvesting by-product from the culture system and the potential applications.