Leveraging microalgae as a sustainable ingredient for meat analogues.

As the world's population and income levels continue to rise, there is a substantial increase in the demand for meat, which poses significant environmental challenges due to large-scale livestock production. This review explores the potential of microalgae as a sustainable protein source for meat analogues. The nutritional composition, functional properties, and environmental advantages of microalgae are analyzed. Additionally, current obstacles to large-scale microalgal food production are addressed, such as strain development, contamination risks, water usage, and downstream processing. The challenges associated with creating meat-like textures and flavors using techniques like extrusion and emulsion formation with microalgae are also examined. Lastly, considerations related to consumer acceptance, marketing, and regulation are summarized. By focusing on improvements in cultivation, structure, sensory attributes, and affordability, microalgae demonstrate promise as a transformative and eco-friendly protein source to enhance the next generation of meat alternatives.

Fabrication of flexible chitosan film reinforced with pulping by-product lignosulfonates for cherry-tomato preservation.

The massive production of food waste and plastic pollution necessitates innovative solutions. This study reports the first fabrication of a flexible chitosan (CH) film reinforced with lignosulfonate (LS) derived from pulping byproduct as a sustainable alternative to synthetic food packaging. The CH/LS composite film was prepared by a simple casting method with varying LS contents of 1 % and 2 %. Compared to CH film, the addition of 2 % LS increased the tensile strength by over 4 times and decreased water vapor permeability by 11 %. Moreover, the CH/LS film exhibited excellent UV-shielding properties. This novel use of LS to reinforce CH film presents an eco-friendly active packaging material. When used to package cherry tomatoes for 2 weeks, the CH/LS film effectively maintained fruit freshness and hardness while minimizing weight loss. This work provides new scientific evidence on the optimized preparation and application of CH/LS composite films from renewable resources for food preservation.

Mitigation of oxidative stress damage caused by abiotic stress to improve biomass yield of microalgae: A review.

Microalgae have been recognized as emerging cell factories due to the high value-added bio-products. However, the balance between algal growth and the accumulation of metabolites is always the main contradiction in algal biomass production. Hence, the security and effectiveness of regulating microalgal growth and metabolism simultaneously have drawn substantial attention. Since the correspondence between microalgal growth and reactive oxygen species (ROS) level has been confirmed, improving its growth under oxidative stress and promoting biomass accumulation under non-oxidative stress by exogenous mitigators is feasible. This paper first introduced ROS generation in microalgae and described the effects of different abiotic stresses on the physiological and biochemical status of microalgae from these aspects associated with growth, cell morphology and structure, and antioxidant system. Secondly, the role of exogenous mitigators with different mechanisms in alleviating abiotic stress was concluded. Finally, the possibility of exogenous antioxidants regulating microalgal growth and improving the accumulation of specific products under non-stress conditions was discussed.

Extraction and surface modification of cellulose fibers and its reinforcement in starch-based film for packaging composites.

BACKGROUND: Cellulose extraction from gloss art paper (GAP) waste is a recycling strategy for the abundance of gloss art paper waste. Here, a study was conducted on the impact of ultrasonic homogenization for cellulose extraction from GAP waste to improve the particle size, crystallinity, and thermal stability. RESULTS: At treatment temperature of 75.8 °C, ultrasonic power level of 70.3% and 1.4 h duration, cellulose with properties of 516.4 nm particle size, 71.5% crystallinity, and thermal stability of 355.2 °C were extracted. Surface modification of cellulose GAP waste with H3PO4 hydrolysis and 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) oxidation was done followed by starch reinforcement. Surface hydrophobicity and mechanical strength were increased for H3PO4 hydrolysis and TEMPO oxidation starch-cellulose. No reduction of thermal properties observed during the treatment, while increment of crystallinity index up to 47.65-59.6% was shown. Neat starch film was more transparent, followed by starch-TEMPO film and starch-H3PO4 film, due to better homogeneity. CONCLUSIONS: The cellulose GAP reinforced starch film shows potential in developing packaging materials and simultaneously provide an alternative solution of GAP waste recycling.

Effect of phytochemical vanillic acid on the growth and lipid accumulation of freshwater microalga Euglena gracilis.

A feasible approach against the low yield of microalgae biomass involves the use of a stimulator for microalgal growth. In this research, vanillic acid present in the hydrolysate of agricultural waste, was applied to the cultivation of unicellular microalga Euglena gracilis. At the optimal dosage of 800 mg L-1 vanillic acid, biomass yield at treatment increased 2.08-fold. Correspondingly, the content of chlorophyll a and carotenoids was 3.48 and 2.69 fold than of the control ground, respectively. Increased in cell aspect ratio demonstrated that the alga was more active after vanillic acid treatment. Furthermore, relative lipid and carbohydrate content were analyzed using Fourier transform infrared spectroscopy, the result showed that vanillic acid increased the lipid content in algal cells without sacrificing biomass, which would be a promising way for future biofuel production.

Enhanced crystallinity and thermal properties of cellulose from rice husk using acid hydrolysis treatment.

Cellulose was extracted from rice husk (RH) using an integrated delignification process using alkaline treatment and acid hydrolysis (concentrated HNO3) for lignocellulosic biomass dissolution. Cellulose yield and quality were assessed through analysis of lignocellulosic content, thermogravimetric, functional group, X-ray diffraction, and surface morphology. HNO3 treatment showed an increment (2.01-fold) in the cellulose content and some enhancement in the crystallinity of cellulose (up to 40.8%). A slight increase was observed in thermal properties from 334.6 °C to 339.3 °C. Economic analysis showed chlorine extraction produce higher cellulose recovery (58%) as compared to HNO3 (26.7%) with the total cost of operation using HNO3 was double compared to chlorine extraction. The economic feasibility of HNO3 can be improved using various progress in the pre-treatment process, chemical recycling and cellulose recovery process since adopting it is crucial for environmental sustainability.

Enhancement of biomass yield and lipid accumulation of freshwater microalga Euglena gracilis by phenolic compounds from basic structures of lignin.

Introducing biomass-derived additives into microalgae cultivation to increase its yield has been regarded as a more cost-effective and environment-friendly method compared with gene-editing and nutrients supplementation. In this research, feasibility of three major phenolic compounds from lignin's basic structures (guaiacyl-, hydroxyphenyl- and syringyl- types) for freshwater microalga Euglena gracilis cultivation was evaluated. The results indicated that trans-4-hydroxy-3-methoxycinnamic acid (HMA), 4-hydroxybenzaldehyde (HBA), and syringaldehyde (SRA) could all promote microalgae growth in a phytohormone-like role, and the highest promotion effect was achieved under HMA treatment. HMA at 0.5 g·L-1 enhanced the cell biomass yield by 2.30 times, while HBA and SRA at the concentration of 0.1 g·L-1 increased the yield by 1.30 and 1.21 times, respectively. In addition, increased carotenoids and lipid biosynthesis were also observed under the treatments of phenolic compounds, which would contribute to the microalgae biofuel production, since the growth and lipid accumulation of E. gracilis were simultaneously enhanced.

Harvesting of Arthrospira platensis by flocculation with phytic acid from rice bran.

The recovery of algal biomass is one of the critical steps involved in the commercial production of beneficial metabolites from Arthrospira platensis. Efficient and safe harvesting methods that do not sacrifice quality of final product are important for commercial application. Phytic acid (PA) is a natural non-toxic phytochemical widely distributed in plant tissues. Effect of PA from rice bran on the growth, trichome morphology such as spiral number and algal filament length, and harvesting efficiency of A. platensis were investigated. Cells aggregated into large cell flocs after the addition of PA in the medium, and algal spiral number and filament length increased. UV-vis spectra indicated the interactions between PA and algal cells. Adding PA at stationary growth phase is a good strategy for harvesting, since no adverse effect to biomass growth and harvesting efficiency. Harvesting efficiency of 95.69% at 0.5% (v/v) PA was superior to other conventional harvesting methodologies. ABBREVIATIONS: PA: Phytic acid; PUFAs: Polyunsaturated fatty acids; FAO: Food and Agriculture Organization; γ-PGA: Poly (γ-glutamic acid); CNF: Cellulose nanofibrils; NIES: National Institute for Environmental Studies; SOT: Spirulina-Ogawa-Terui; CG: Control group; pI: Isoelectric point.

Effect of two lignocellulose related sugar alcohols on the growth and metabolites biosynthesis of Euglena gracilis.

It is an effective solution to overcome the bottlenecks of commercial production of microalgal biomass by providing cost-effective and environment-friendly organic carbon sources for microalgal mixotrophic growth. In this study, effects of lignocellulose-related mannitol and xylitol on the growth, photosynthetic pigment content, cell morphology, and metabolites biosynthesis of freshwater microalga Euglena gracilis were investigated. The results revealed that both mannitol and xylitol effectively promoted the growth of E. gracilis, and at the optimal dosage of 4 g·L-1, the biomass yield was increased by 4.64-fold and 3.18-fold, respectively. Increase of cell aspect ratio was only observed in mannitol treatment groups, indicating that E. gracilis had different physiological responses to mannitol and xylitol. Fourier transform infrared spectroscopy combined with multivariate analysis was applied to analyze the cellular components. The lipid content of E. gracilis was significantly promoted by these two sugar alcohols, which would increase its potential in biofuel production.

Finding of phytase: Understanding growth promotion mechanism of phytic acid to freshwater microalga Euglena gracilis.

To better understand the promotion effect of phytic acid and its uptake mechanism in freshwater microalga Euglena gracilis, cell growth, photosynthetic pigment content and cell morphology of E. gracilis were evaluated under four conditions: phosphorus deficient group (CMP-), single phosphate treatment group (CMP+), single phytic acid treatment group (CMPA-), and phosphate-phytic acid mixed treatment group (CMPA+). The results showed that phytic acid could serve as the sole phosphorus source for the growth of E. gracilis, and phytase which catalyzes the hydrolysis of phytic acid was discovered for the first time in E. gracilis. Fourier transform infrared spectroscopy combined with multivariate analysis showed the good recognition of metabolites from different culture conditions especially focusing on relative carbohydrate or lipid contents. Phytic acid derived from agro-wastes is a cheap growth promoter for E. gracilis, and this E. gracilis with high nutritional value is applicable to animal feed while minimizing environmental impact.

Effect of Air Nanobubble Water on the Growth and Metabolism of Haematococcus lacustris and Botryococcus braunii.

Miniature air bubbles with a diameter of less than 200 nm were generated by a nanobubble aerator, and nanobubble water (NBW) was eventually obtained using the gas-liquid mixing system with hydrodynamic function. As the air bubbles have long lifetime and high gas solubility in the liquids, NBW is stable in nature and inside contains sufficient dissolved oxygen. At present, there is no report on the use of NBW to replace ordinary water to cultivate microalgae. In this research, effect of NBW on the growth and metabolism of different microalgae, including Haematococcus lacustris and Botryococcus braunii was investigated. The result demonstrated that the growth of H. lacustris and B. braunii was increased by NBW and the highest promotion ratio was up to 44% and 26%, respectively. For H. lacustris, the astaxanthin content in the NBW treatment group was also improved compared to the control group. As the main product of B. braunii, lipid content in the dry matter was decreased after the treatment of NBW, but total lipid production was significantly higher than that of the control group. In general, NBW could serve as the potentially effective tool to promote the growth of microalgae in the future.

Organic Thin Paper of Cellulose Nanofiber/Polyaniline Doped with (±)-10-Camphorsulfonic Acid Nanohybrid and Its Application to Electromagnetic Shielding.

A superior electrical conductivity of 38.5 S/cm and an electromagnetic shielding (EMS) effectiveness of -30 dB (-545 dB/mm) across a wide frequency range of 0-15 GHz, including the X-band, were achieved with thin organic paper of (55 µm) cellulose nanofiber (CNF)/polyaniline (PANI) doped with (±)-10-camphorsulfonic acid nanohybrid. Both electrical conductivity and EMS effectiveness of the PANI-coated CNF were strongly affected by the amount and type of dopant, which could be tunable after fabrication process via simple in situ oxidative polymerization of aniline. Flexible and free-standing film was obtained, since CNF provides good mechanical property without diminishing the electrical property of PANI.

Mechanical characterisation of lignocellulosic fibres using toy bricks tensile tester.

This paper demonstrates the potential use of toy-bricks as the building block of a mechanical tensile testing instrument for the mechanical characterisation of natural fibres. A table-top tensile testing instrument was developed using LEGO parts (Mindstorms EV3 and Technics) and a 2 kg capacity load cell, whereas deformation modes were programmed in an open source programming language. Experimental work was conducted on oil palm fibres under different tensile modes (i.e. constant deformation, triple-twisted-tension and deformation-relaxation modes), which showed anisotropic-viscoelastic behaviour, and microstructural damages due to deformation.

Growth promotion of Euglena gracilis by ferulic acid from rice bran.

A significant growth promotion of Euglena gracilis was achieved by simply adding ferulic acid from rice bran without diminishing the accumulation of valuable products like paramylon. E. gracilis is a freshwater microalga that is widely applied in cosmetics, food, medicine, and supplements, and it is considered a potential source of biofuel. It is therefore important to enhance its yield at a lower cost for its commercial viability. Introducing a growth regulator derived from agro waste is considered a cheaper and safer strategy to improve biomass productivity compared with other alternatives such as implementing genetic engineering or adding nutrients and plant hormones as growth stimulator. The effect of ferulic acid derived from rice bran on the growth and metabolism of E. gracilis was investigated in this study. To aid in the dissolution of ferulic acid, 1% dimethyl sulfoxide (DMSO) was added to Cramer-Myers medium. Ferulic acid could alleviate the inhibitory effect of DMSO and significantly promoted the growth of E. gracilis. It was found that cell density was 2.5 times greater than that of the control group and 3.6 times greater than that of the negative control group when 500 mg/L of ferulic acid was added. In addition, the photosynthetic pigment content, especially chlorophyll a, increased with increasing ferulic acid concentrations. The total paramylon production would also be enhanced by ferulic acid since the number of cells increased without reducing the cellular content of paramylon.

Growth promotion of Spirulina by steelmaking slag: application of solubility diagram to understand its mechanism.

A solubility diagram was employed to understand growth promotion of Arthrospira (Spirulina) platensis by steelmaking slag (SMS). The growth promotion effect of 112 % of freshwater microalga A. platensis was obtained using 5 g/L SMS. However, metabolites, such as pigments, and protein content of A. platensis were not significantly affected. Several metals dissolved in Spirulina-Ogawa-Terui medium were detected by inductively coupled plasma atomic emission spectrometry just after the addition of SMS. The solubility diagram provides information on the chemical speciation of metal elements based on pH and concentration. It is a useful tool to understand the effect of metals on microalgal growth. The metal elements used to control microalgal growth are essential minerals but also act as a source of oxidative stress. Regarding the affecting mechanism of SMS, iron may be the primary element regulating microalgal growth via pathway involving reactive oxygen species, as revealed by superoxide dismutase assay.

Chitosan nanofibers fabricated by combined ultrasonic atomization and freeze casting.

Aligned chitosan nanofibers exhibiting diameters smaller than 100 nm were easily prepared by combining ultrasonic atomization with freeze casting. A major advantage of this approach is the use of distilled water as main solvent. Scanning electron microscopy demonstrated that fiber diameter and morphology mainly depended on the atomizing tools, freezing temperature, and chitosan solution viscosity. Minimum diameter and uniform orientation were achieved using an electric flosser as an atomizing tool, liquid nitrogen as a coolant, 0.4 wt% aqueous chitosan solution (molecular weight = 22 kDa), and a small amount of lactic acid as solvent at 0 °C. The resulting chitosan nanofibers may find application in biomedical and food engineering. Moreover, this new technology may be applicable to other natural and synthetic water-soluble polymers.

Bioconversion of glycerol for bioethanol production using isolated Escherichia coli SS1

Bioconverting glycerol into various valuable products is one of glycerol's promising applications due to its high availability at low cost and the existence of many glycerol-utilizing microorganisms. Bioethanol and biohydrogen, which are types of renewable fuels, are two examples of bioconverted products. The objectives of this study were to evaluate ethanol production from different media by local microorganism isolates and compare the ethanol fermentation profile of the selected strains to use of glucose or glycerol as sole carbon sources. The ethanol fermentations by six isolates were evaluated after a preliminary screening process. Strain named SS1 produced the highest ethanol yield of 1.0 mol: 1.0 mol glycerol and was identified as Escherichia coli SS1 Also, this isolated strain showed a higher affinity to glycerol than glucose for bioethanol production.

Bioconversion of glycerol for bioethanol production using isolated Escherichia coli ss1.

Bioconverting glycerol into various valuable products is one of glycerol's promising applications due to its high availability at low cost and the existence of many glycerol-utilizing microorganisms. Bioethanol and biohydrogen, which are types of renewable fuels, are two examples of bioconverted products. The objectives of this study were to evaluate ethanol production from different media by local microorganism isolates and compare the ethanol fermentation profile of the selected strains to use of glucose or glycerol as sole carbon sources. The ethanol fermentations by six isolates were evaluated after a preliminary screening process. Strain named SS1 produced the highest ethanol yield of 1.0 mol: 1.0 mol glycerol and was identified as Escherichia coli SS1 Also, this isolated strain showed a higher affinity to glycerol than glucose for bioethanol production.

Nitrification of high-strength ammonium landfill leachate with microbial community analysis using fluorescence in situ hybridization (FISH).

Nitrification of mature sanitary landfill leachate with high-strength of N-NH(4) + (1080-2350 mg L(-1)) was performed in a 10 L continuous nitrification activated sludge reactor. The nitrification system was acclimatized with synthetic leachate during feed batch operation to avoid substrate inhibition before being fed with actual mature leachate. Successful nitrification was achieved with an approximately complete ammonium removal (99%) and 96% of N-NH(4) + conversion to N-NO(-) (3) . The maximum volumetric and specific nitrification rates obtained were 2.56 kg N-NH(4) (+) m(-3) day(-1) and 0.23 g N-NH(4) ( +) g(-1) volatile suspended solid (VSS) day(-1), respectively, at hydraulic retention time (HRT) of 12.7 h and solid retention time of 50 days. Incomplete nitrification was encountered when operating at a higher nitrogen loading rate of 3.14 kg N-NH(4) (+) m(-3) day(-1). The substrate overloading and nitrifiers competition with heterotrophs were believed to trigger the incomplete nitrification. Fluorescence in situ hybridization (FISH) results supported the syntrophic association between the ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria. FISH results also revealed the heterotrophs as the dominant and disintegration of some AOB cell aggregates into single cells which further supported the incomplete nitrification phenomenon.

Flocculation characteristics of an isolated mutant flocculent Saccharomyces cerevisiae strain and its application for fuel ethanol production from kitchen refuse.

A stable mutant flocculent yeast strain of Saccharomyces cerevisiae KRM-1 was isolated during repeated-batch ethanol fermentation using kitchen refuse as the medium. The mechanism of flocculation and interaction with the medium was investigated. According to sugar inhibition assay, it was found that the mutant flocculent strain was a NewFlo phenotype. Flocculation was completely inhibited by protease, proteinase K and partially reduced by treatments with carbohydrate-hydrolyzing enzymes. Flocculation ability showed no difference for pH 3.0-6.0. Furthermore, the mutant flocculent yeast provided repeated-batch cultivations employing cell recycles by flocculation over 10 rounds of cultivation for the production of ethanol from kitchen refuse medium, resulting in relatively high productivity averaging 8.25 g/L/h over 10 batches and with a maximal of 10.08 g/L/h in the final batch. Cell recycle by flocculation was fast and convenient, and could therefore be applicable for industrial-scale ethanol production.