A look into Phaffia rhodozyma biorefinery: From the recovery and fractionation of carotenoids, lipids and proteins to the sustainable manufacturing of biologically active bioplastics

Maximizing Haematococcus biorefineries: Ionic liquid-based astaxanthin recovery, biocosmetic formulation, solar cell applications, and biofertilizer valorization

Microalgae, particularly Haematococcus pluvialis, produce astaxanthin (AXT), a potent antioxidant with growing potential in the food, pharmaceutical, biocosmetic, and renewable energy sectors. This study proposes an integrated biorefinery model that employs advanced extraction processes, including bio-based ionic liquids, to efficiently recover AXT from H. pluvialis while minimizing environmental impact. The resulting platform strategically repurposes the post-extraction biomass as a biofertilizer, thus contributing to zero-waste objectives. By uniting biocosmetics, solar energy applications, and agriculture within a single framework, this model underscores the synergy between economic feasibility and ecological responsibility, highlighting the transformative role of microbial-derived AXT in sustainable, high-value product development.

Eco-sustainable, edible, biodegradable and antioxidant pectin and bacterial cellulose films loaded with coconut oil for strawberry preservation

Strawberry is one of the most problematic fresh fruits susceptible to damage or mold due to their sensitive skin. For this, we developed films made of bacterial cellulose [BC, 25 % (w/w)], pectin [P, 75 % (w/w)] loaded with coconut oil for strawberry preservation. XRD patterns of the BC showed three distinct peaks at Bragg angles (2θ) of 14.6°, 16.9°, and 22.7°, indicating the structural characteristics of cellulose I. CG-MS demonstrated that coconut oil contained triacylglycerols like lauric acid, linoleic acid, and dodecanoic acid. Moreover, coconut oil showed antioxidant activity of about 50 % and antimicrobial activity in yeast extracted from strawberries. FTIR spectroscopy, TGA/DTG, mechanical testing, water vapor permeability, AFM and SEM images showed that the oil was successfully incorporated into the film. Next, mass loss and swelling degree and wettability studies revealed that formed films maintained hydrophobic characteristics. In fact, these films presented a high-water vapor barrier because preserved a major part of the characteristics of the biocellulose, turning the bioplastics inert to water. In addition, coconut oil loaded into BC + P bioplastic presented low release due to its hydrophobicity character. Despite this, our bioplastic worked as a mechanical barrier, protecting the fruits from microorganisms and other forms of damage. Furthermore, antioxidant activity from both film-formed was similar (28 %), and these bioplastics preserved the strawberries for 192 h, whereas uncoated fruits degraded at 72 h. Indeed, our bioplastics were more effective in reducing fruit mass loss, especially BC + P + O film. Our findings showed that the essential oil acted as a reducing agent of strawberry mass loss, decreasing its skin transpiration, being an inexpensive and feasible alternative for fruits preservation.

Microbial astaxanthin-encapsulated polymeric micelles from yeast Phaffia rhodozyma for personalized bioactive colored natural rubber latex bandages

This study explores the development of bioactive, colored natural rubber latex (NRL) bandages by incorporating astaxanthin (AXT), a carotenoid with potent antioxidant and anti-inflammatory properties. AXT is produced by the yeast Phaffia rhodozyma under various light conditions to improve AXT biosynthesis and encapsulated in polymeric micelles to enhance its solubility and stability. The encapsulated AXT is then integrated into NRL bandages, imparting a orange-red hue and potentially therapeutic benefits. Physicochemical characterizations, including UV-Vis spectroscopy and FTIR, reveal interactions between AXT and the micelle components. The bandages exhibit improved hydrophilicity and maintain their thermal stability post-AXT incorporation. Antioxidant capacity assessments show that the NRL bandages retain a significant portion of AXT's antioxidant properties, which can aid in wound healing. The release profile of AXT from the bandages demonstrates an initial burst followed by sustained release, indicating effective delivery of the carotenoid. This innovative approach combines aesthetic appeal with biomedical advantages, offering a personalized solution for wound care applications.

Synergistic effects of Tween 20 and ethephon on yeast oil and β-carotene co-production by Rhodosporidium toruloides using purified biodiesel-derived crude glycerol as an alternative carbon source

This study investigated the impact of chemical inducers on the co-production of yeast oil (YO) and β-carotene from purified biodiesel-derived crude glycerol. The objective was to enhance YO and β-carotene co-production in Rhodosporidium toruloides through the application of individual and combined inducers at both flask and bioreactor scales. Among the individual inducers, 1 % w/v Tween 20 (TW) and 10 ppm ethephon (EP) significantly increased total yeast oil (TO) and total β-carotene (TC) concentrations, respectively. When TW and EP were used together, TO and TC production increased by 2.0 and 2.6-fold, respectively in the bioreactor compared to the flask. The YO primarily consisted of C16 and C18 long-chain fatty acids, and the β-carotene produced showed functional similarities to commercial β-carotene. This research highlights the potential of biodiesel waste as a sustainable feedstock for co-producing YO and β-carotene, with the dual-inducer strategy providing a simple and effective method for enhancing production efficiency.

Biotechnological potential of red yeast isolated from birch forests in Poland

OBJECTIVES

This study aimed to isolate red yeast from sap, bark and slime exudates collected from Polish birch forests and then assessment of their biotechnological potential.

RESULTS

24 strains of red yeast were isolated from the bark, sap and spring slime fluxes of birch (Betula pendula). Strains belonging to Rhodotorula mucilaginosa (6), Rhodosporidiobolus colostri (4), Cystrofilobasidium capitaum (3), Phaffia rhodozyma (3) and Cystobasidium psychroaquaticum (3) were dominant. The highest efficiency of carotenoid biosynthesis (5.04 mg L-1) was obtained by R. mucilaginosa CMIFS 004, while lipids were most efficiently produced by two strains of P. rhodozyma (5.40 and 5.33 g L-1). The highest amount of exopolysaccharides (3.75 g L-1) was produced by the R. glutinis CMIFS 103. Eleven strains showed lipolytic activity, nine amylolytic activity, and only two proteolytic activity. The presence of biosurfactants was not found. The growth of most species of pathogenic moulds was best inhibited by Rhodotorula yeasts.

CONCLUSION

Silver birch is a good natural source for the isolation of new strains of red yeast with wide biotechnological potential.

Laponite-Modified Biopolymers as a Conformable Substrate for Optoelectronic Devices

Biopolymers such as carboxymethyl cellulose and hyaluronic acid are alternative substrates for conformable organic light-emitting diodes (OLEDs). However, drawbacks such as mechanical stress susceptibility can hinder the device's performance under stretched conditions. To overcome these limitations, herein, we developed a nanocomposite based on CMC/HA (carboxymethyl cellulose/hyaluronic acid) and synthetic Laponite, intending to improve the mechanical strength without compromising the film flexibility and transparency (transmittance >80%; 380-700 nm) as substrates for conformable OLEDs. From XRD, FTIR, CP-MAS NMR, and TGA/DTG characterization techniques, it was possible to conclude the presence of Laponite randomly dispersed between the polymer chains. CMC/HA with 5% (w/w) Laponite, CMC/HA 5, presented a higher tensile strength (370.6 MPa) and comparable Young's modulus (51.0 ± 1.2 MPa) in comparison to the nanocomposites and pristine films, indicating a better candidate for the device's substrates. To produce the OLED, the multilayer structure ITO/MoO3/NPB/TCTA:Ir(ppy)3/TPBi:Ir(ppy)3/BPhen/LiF was deposited onto the CMC/HA 5 substrate. The OLEDs fabricated using CMC/HA 5 substrates showed higher luminance (12 kcd/m2) and irradiance (0.9 mW/cm2) values when compared with those based on commercial bacterial cellulose. However, the same device presented a lower efficiency (3.2 cd/A) due to a higher current density. Moreover, the OLED fabricated onto the Laponite-modified biopolymer presented reproducible behavior when submitted to continuous bending stress. Thus, CMC/HA 5 demonstrates potential as a transparent conductor substrate for biopolymer-based OLEDs with comparable performance to commercial bacterial cellulose features.

Is the carotenoid production from Phaffia rhodozyma yeast genuinely sustainable? a comprehensive analysis of biocompatibility, environmental assessment, and techno-economic constraints

Microorganisms, such as yeasts, filamentous fungi, bacteria, and microalgae, have gained significant attention due to their potential in producing commercially valuable natural carotenoids. In recent years, Phaffia rhodozyma yeasts have emerged as intriguing non-conventional sources of carotenoids, particularly astaxanthin and β-carotene. However, the shift from academic exploration to effective industrial implementation has been challenging to achieve. This study aims to bridge this gap by assessing various scenarios for carotenoid production and recovery. It explores the use of ionic liquids (ILs) and bio-based solvents (ethanol) to ensure safe extraction. The evaluation includes a comprehensive analysis involving Life Cycle Assessment (LCA), biocompatibility assessment, and Techno-Economic Analysis (TEA) of two integrated technologies that utilize choline-based ILs and ethanol (EtOH) for astaxanthin (+β-carotene) recovery from P. rhodozyma cells. This work evaluates the potential sustainability of integrating these alternative solvents within a yeast-based bioeconomy.

Eco-sustainable coatings based on chitosan, pectin, and lemon essential oil nanoemulsion and their effect on strawberry preservation

Films and coatings manufactured with bio-based renewable materials, such as biopolymers and essential oils, could be a sustainable and eco-friendly alternative for protecting and preserving agricultural products. In this work, we developed films and coatings from pectin and chitosan to protect strawberries (Fragaria x ananassa Duch.) from spoilage and microbial contamination. We developed three coatings containing equal amounts of glycerol and Sicilian lemon essential oil (LEO) nanoemulsion. We identified seventeen chemicals from LEO by GC-MS chromatogram, including d-limonene, α-Pinene, β-Pinene, and γ-Terpinene. The pectin and chitosan coatings were further characterized using different physicochemical, mechanical, and biological methods. The films demonstrated satisfactory results in strength and elongation at the perforation as fruit packaging. In addition, the coatings did not influence the weight and firmness of the strawberry pulps. We observed that 100 % essential oil was released in 1440 min resulting from the erosion process. Also, the oil preserved the chemical stability of the films. Antioxidant activity (AA), measured by Electron Paramagnetic Resonance (EPR), showed that the coatings loaded with 2 % LEO nanoemulsion (PC + oil) showed that almost 50 % of AA from LEO nanoemulsion was preserved. The chitosan and the pectin-chitosan coatings (PC + oil) inhibited filamentous fungi and yeast contaminations in strawberries for at least 14 days, showing a relationship between the AA and antimicrobial results.

Astaxanthin production using Paracoccus carotinifaciens: a way forward?

Paracoccus carotinifaciens could be considered a key microbial factory for obtaining healthier natural products such as astaxanthin (AXT), thus contributing to a bioeconomy. Short cultivation time, high production titers, and thin cell wall are the main advantages that make this bacterium promising in the development of sustainable third-generation biorefineries.

Microbial astaxanthin: from bioprocessing to the market recognition

The attractive biological properties and health benefits of natural astaxanthin (AXT), including its antioxidant and anti-carcinogenic properties, have garnered significant attention from academia and industry seeking natural alternatives to synthetic products. AXT, a red ketocarotenoid, is mainly produced by yeast, microalgae, wild or genetically engineered bacteria. Unfortunately, the large fraction of AXT available in the global market is still obtained using non-environmentally friendly petrochemical-based products. Due to the consumers concerns about synthetic AXT, the market of microbial-AXT is expected to grow exponentially in succeeding years. This review provides a detailed discussion of AXT's bioprocessing technologies and applications as a natural alternative to synthetic counterparts. Additionally, we present, for the first time, a very comprehensive segmentation of the global AXT market and suggest research directions to improve microbial production using sustainable and environmentally friendly practices. KEY POINTS: • Unlock the power of microorganisms for high value AXT production. • Discover the secrets to cost-effective microbial AXT processing. • Uncover the future opportunities in the AXT market.