Use of agroindustrial byproducts as substrate for production of carotenoids with antioxidant potential by wild yeasts

Carotenoids production by Rhodosporidium paludigenum yeasts: Characterization of chemical composition, antioxidant and antimicrobial properties

The high market potential imposed by natural carotenoids has turned the scientific interest in search for new strains, capable of synthesizing a wide spectrum of these pigments. In this study, Rhodosporidium paludigenum NCYC 2663 and 2664 were investigated for carotenoids production and lipid accumulation utilizing different carbon sources (glucose, fructose, sucrose, mixture of glucose: galactose). Strain R. paludigenum 2663 produced the highest total carotenoids titer (2.21 mg/L) when cultivated on sucrose, together with 4 g/L lipids (30% w/w content) and 7 g/L exopolysaccharides. In the case of R. paludigenum 2664, glucose favored the production of 2.93 mg/L total carotenoids and 1.57 g/L lipids (31.8% w/w content). Analysis of the chemical profile during fermentation revealed that β-carotene was the prominent carotenoid. Strain 2663 co-produced γ-carotene, torulene and torularhodin in lower amounts, whereas 2664 synthesized almost exclusively β-carotene. The produced lipids from strain 2663 were rich in oleic acid, while the presence of linoleic acid was also detected in the lipoic fraction from strain 2664. The obtained carotenoid extracts exhibited antioxidant (IC50 0.14 mg/mL) and high antimicrobial activity, against common bacterial and fungal pathogenic strains. The results of this study are promising for the utilization of biotechnologically produced carotenoids in food applications.

β-Carotene production from sugarcane molasses by a newly isolated Rhodotorula toruloides L/24-26-1

Production of carotenoids by yeast fermentation is an advantaged technology due to its easy scaling and safety. Nevertheless, carotenoid production needs an economic culture medium and other efficient yeast stains. The study aims to isolate and identify a yeast strain capable of producing carotenoids using a cost-effective substrate. A new strain was identified as Rhodotorula toruloides L/24-26-1, which can produce carotenoids at different pretreated and unpretreated sugarcane molasses concentrations (40 and 80 g/L). The highest biomass concentration (18.6 ± 0.6 g/L) was reached in the culture using 80 g/L of hydrolyzed molasses. On the other hand, the carotenoid accumulation reached the maximum value using pretreated molasses at 40 g/L (715.4 ± 15.1 µg/g d.w). In this case, the β-carotene was 1.5 times higher than that on the control medium. The yeast growth in molasses was not correlated with carotenoid production. The most outstanding production of The DPPH, ABTS, and FRAP tests demonstrated the antioxidant activity of the obtained carotenogenic extracts. This research demonstrated the R. toruloides L/24-26-1 strain biotechnological potential for carotenoid compounds. The yeast produces carotenoids with antioxidant activity in an inexpensive medium, such as sulfuric acid pretreated and unpretreated molasses.

Fungi-derived natural antioxidants

In humans, exogenous antioxidants aid the endogenous antioxidant system to detoxify excess ROS generated during oxidative stress, thereby protecting the body against various diseases and stressful conditions. The majority of natural antioxidants available on the consumer market are plant-based; however, fungi are being recognized as alternative sources of various natural antioxidants such as polysaccharides, pigments, peptides, sterols, phenolics, alkaloids, and flavonoids. In addition, some exogenous antioxidants are exclusively found in fungi. Fungi-derived antioxidants exhibit scavenging activities against DPPH, ABTS, hydroxyl, superoxide, hydrogen peroxide, and nitric oxide radicals in vitro. Furthermore, in vivo models, application of fungal-derived antioxidants increase the level of various antioxidant enzymes, such as catalases, superoxide dismutases, and glutathione peroxidases, and reduce the level of malondialdehyde. Therefore, fungi-derived antioxidants have potential to be used in the food, cosmetic, and pharmaceutical industries. This review summarizes the antioxidant potential of different fungi (mushrooms, yeasts, and molds)-derived natural compounds such as polysaccharides, pigments, peptides, ergothioneine, ergosterol, phenolics, alkaloids, etc.

Simultaneous Lipid and Carotenoid Production via Rhodotorula paludigena CM33 Using Crude Glycerol as the Main Substrate: Pilot-Scale Experiments

Rhodotorula paludigena CM33 is an oleaginous yeast that has been demonstrated to accumulate substantial quantities of intracellular lipids and carotenoids. In this study, crude glycerol, a by-product of biodiesel production, was used as a carbon source to enhance the accumulation of lipids and carotenoids in the cells. The culture conditions were first optimized using response surface methodology, which revealed that the carotenoid concentration and lipid content improved when the concentration of crude glycerol was 40 g/L. Different fermentation conditions were also investigated: batch, repeated-batch, and fed-batch conditions in a 500 L fermenter. For fed-batch fermentation, the maximum concentrations of biomass, lipids, and carotenoids obtained were 46.32 g/L, 37.65%, and 713.80 mg/L, respectively. A chemical-free carotenoid extraction method was also optimized using high-pressure homogenization and a microfluidizer device. The carotenoids were found to be mostly beta-carotene, which was confirmed by HPLC (high pressure liquid chromatography), LC-MS (liquid chromatography-mass spectrometry), and NMR (nuclear magnetic resonance). The results of this study indicate that crude glycerol can be used as a substrate to produce carotenoids, resulting in enhanced value of this biodiesel by-product.

Microbial Pigments: Major Groups and Industrial Applications

Microbial pigments have many structures and functions with excellent characteristics, such as being biodegradable, non-toxic, and ecologically friendly, constituting an important source of pigments. Industrial production presents a bottleneck in production cost that restricts large-scale commercialization. However, microbial pigments are progressively gaining popularity because of their health advantages. The development of metabolic engineering and cost reduction of the bioprocess using industry by-products opened possibilities for cost and quality improvements in all production phases. We are thus addressing several points related to microbial pigments, including the major classes and structures found, the advantages of use, the biotechnological applications in different industrial sectors, their characteristics, and their impacts on the environment and society.

Lignocellulosic biorefineries as a platform for the production of high-value yeast derived pigments - A review

Lignocellulosic byproducts, mainly generated by the agro-industrial sector, have great potential as cost-effective feedstocks for bioprocesses because of their abundant availability and high content of sugar-rich and nutrient-rich elements. This biomass can be employed as a carbon source to produce various molecules using several microorganisms. Yeast strains have shown their capability to metabolize diverse C5 and C6 carbon sources, thereby facilitating their use in the bioprocessing of lignocellulosic biomass. Furthermore, yeasts can produce a wide range of valuable products, including biofuels, enzymes, proteins, and pigments, making them attractive for use in integrated biorefineries. Yeast-derived pigments have versatile applications and are environmentally friendly alternatives to their synthetic counterparts. This review emphasizes the potential of lignocellulosic biomass as a feedstock for producing yeast-derived products with a focus on pigments as valuable molecules. It also proposes a yeast-derived pigment platform utilizing lignocellulosic byproducts and explores its potential integration in biorefineries.

Microalgae, Seaweeds and Aquatic Bacteria, Archaea, and Yeasts: Sources of Carotenoids with Potential Antioxidant and Anti-Inflammatory Health-Promoting Actions in the Sustainability Era

Carotenoids are a large group of health-promoting compounds used in many industrial sectors, such as foods, feeds, pharmaceuticals, cosmetics, nutraceuticals, and colorants. Considering the global population growth and environmental challenges, it is essential to find new sustainable sources of carotenoids beyond those obtained from agriculture. This review focuses on the potential use of marine archaea, bacteria, algae, and yeast as biological factories of carotenoids. A wide variety of carotenoids, including novel ones, were identified in these organisms. The role of carotenoids in marine organisms and their potential health-promoting actions have also been discussed. Marine organisms have a great capacity to synthesize a wide variety of carotenoids, which can be obtained in a renewable manner without depleting natural resources. Thus, it is concluded that they represent a key sustainable source of carotenoids that could help Europe achieve its Green Deal and Recovery Plan. Additionally, the lack of standards, clinical studies, and toxicity analysis reduces the use of marine organisms as sources of traditional and novel carotenoids. Therefore, further research on the processing of marine organisms, the biosynthetic pathways, extraction procedures, and examination of their content is needed to increase carotenoid productivity, document their safety, and decrease costs for their industrial implementation.

Natural Carotenoids: Recent Advances on Separation from Microbial Biomass and Methods of Analysis

Biotechnologically produced carotenoids occupy an important place in the scientific research. Owing to their role as natural pigments and their high antioxidant properties, microbial carotenoids have been proposed as alternatives to their synthetic counterparts. To this end, many studies are focusing on their efficient and sustainable production from renewable substrates. Besides the development of an efficient upstream process, their separation and purification as well as their analysis from the microbial biomass confers another important aspect. Currently, the use of organic solvents constitutes the main extraction process; however, environmental concerns along with potential toxicity towards human health necessitate the employment of "greener" techniques. Hence, many research groups are focusing on applying emerging technologies such as ultrasounds, microwaves, ionic liquids or eutectic solvents for the separation of carotenoids from microbial cells. This review aims to summarize the progress on both the biotechnological production of carotenoids and the methods for their effective extraction. In the framework of circular economy and sustainability, the focus is given on green recovery methods targeting high-value applications such as novel functional foods and pharmaceuticals. Finally, methods for carotenoids identification and quantification are also discussed in order to create a roadmap for successful carotenoids analysis.

Production of Enriched Biomass by Carotenogenic Yeasts Cultivated on by-Products of Poultry Processing-A Screening Study

Carotenogenic yeasts are a group of microorganisms producing valuable metabolites such as carotenoids, ergosterol, ubiquinone or fatty acids. Their exceptional adaptability allows them to grow in diverse conditions. Owing to their extracellular lipase activity, they are capable of processing many lipid-type waste substrates. This study discusses the processing of poultry waste, specifically fat and feathers by using carotenogenic yeasts. Poultry fat does not require any pre-treatment to be utilized by yeast, but hydrolytic pre-treatment is required for the utilization of the nitrogen contained in feathers. Glycerol was used as a supplementary substrate to support the culture in the early stages of growth. Seven yeast strains were used for the experiments, of which the strain Rhodotorula mucilaginosa CCY19-4-25 achieved exceptional results of biomass production: 29.5 g/L on poultry fat + 10% glycerol at C/N ratio 25 and 28.3 g/L on media containing poultry fat + 25% glycerol at C/N 50. The bioreactor cultivation of the Rhodosporidium toruloides strain in media containing glycerol and feather hydrolysate as a nitrogen substrate achieved a biomass yield of 34.92 g/L after 144 h of cultivation. The produced enriched yeast biomass can be used as a component for poultry feeding; thus, the study is performed under the biorefinery concept.

Growth Potential of Selected Yeast Strains Cultivated on Xylose-Based Media Mimicking Lignocellulosic Wastewater Streams: High Production of Microbial Lipids by Rhodosporidium toruloides

The potential of Rhodosporidium toruloides, Candida oleophila, Metschnikowia pulcherima, and Cryptococcus curvatus species to produce single-cell-oil (SCO) and other valuable metabolites on low-cost media, based on commercial-type xylose, was investigated. Rhodosporidium strains were further evaluated in shake-flasks using different lignosulphonate (LS) concentrations, in media mimicking waste streams derived from the paper and pulp industry. Increasing the LS concentration up to 40 g/L resulted in enhanced dry cell weight (DCW) while SCO production increased up to ~5.0 g/L when R. toruloides NRRL Y-27012 and DSM 4444 were employed. The intra-cellular polysaccharide production ranged from 0.9 to 2.3 g/L in all fermentations. Subsequent fed-batch bioreactor experiments with R. toruloides NRRL Y-27012 using 20 g/L of LS and xylose, led to SCO production of 17.0 g/L with maximum lipids in DCW (YL/X) = 57.0% w/w. The fatty acid (FA) profile in cellular lipids showed that oleic (50.3–63.4% w/w) and palmitic acid (23.9–31.0%) were the major FAs. Only SCO from batch trials of R. toruloides strains contained α-linolenic acid. Media that was supplemented with various LS concentrations enhanced the unsaturation profile of SCO from R. toruloides NRRL Y-27012. SCO from R. toruloides strains could replace plant-based commodity oils in oleochemical-operations and/or it could be micro- and nano-encapsulated into novel food-based formulas offering healthier food-products.

Coproduction of Microbial Oil and Carotenoids within the Circular Bioeconomy Concept: A Sequential Solid-State and Submerged Fermentation Approach

The main objective of integrative biorefinery platforms is to propose efficient green methodologies addressed to obtain high-value compounds with low emissions through biochemical conversions. This work first screened the capacity of various oleaginous yeast to cosynthesize high-value biomolecules such as lipids and carotenoids. Selected strains were evaluated for their ability to coproduce such biocompounds in the waste-based media of agro-food (brewer’s spent grain, pasta processing waste and bakery waste). Carbon and nitrogen source feedstock was obtained through enzymatic hydrolysis of the agro-food waste, where up to 80% of total sugar/starch conversion was obtained. Then, the profitability of the bioprocess for microbial oil (MO) and carotenoids production by Sporobolomyces roseus CFGU-S005 was estimated via simulation using SuperPro Designer®. Results showed the benefits of establishing optimum equipment scheduling by identifying bottlenecks to increase profitability. Sensitivity analysis demonstrated the impact of MO price and batch throughput on process economics. A profitable process was achieved with a MO batch throughput of 3.7 kg/batch (ROI 31%, payback time 3.13 years). The results revealed areas that require further improvement to achieve a sustainable and competitive process for the microbial production of carotenoids and lipids.

Biological Approaches for Extraction of Bioactive Compounds From Agro-industrial By-products: A Review

Bioactive compounds can provide health benefits beyond the nutritional value and are originally present or added to food matrices. However, because they are part of the food matrices, most bioactive compounds remain in agroindustrial by-products. Agro-industrial by-products are generated in large quantities throughout the food production chain and can—when not properly treated—affect the environment, the profit, and the proper and nutritional distribution of food to people. Thus, it is important to adopt processes that increase the use of these agroindustrial by-products, including biological approaches, which can enhance the extraction and obtention of bioactive compounds, which enables their application in food and pharmaceutical industries. Biological processes have several advantages compared to nonbiological processes, including the provision of extracts with high quality and bioactivity, as well as extracts that present low toxicity and environmental impact. Among biological approaches, extraction from enzymes and fermentation stand out as tools for obtaining bioactive compounds from various agro-industrial wastes. In this sense, this article provides an overview of the main bioactive components found in agroindustrial by-products and the biological strategies for their extraction. We also provide information to enhance the use of these bioactive compounds, especially for the food and pharmaceutical industries.

The Evaluation of Arthrospira platensis Bioactivity and their Dietary Supplementation to Nile Tilapia Vegetarian Diet on Growth Performance, Feed Utilization, Body Composition and Hemato-Biochemical Parameters

The present study aimed to identify the carotenoid content and evaluate the antioxidant activities of spirulina, Arthrospira platensis (in vitro), and the effect of its supplementation to a vegetarian diet on growth performance, feed utilization, body proximate composition and physiological status of Nile tilapia, Oreochromis niloticus (in vivo). The carotenoid content of spirulina was identified by UPLC-MS/MS and showed that trans and cis β-carotene were the major carotenoids (88.3%) followed by β-cryptoxanthin and zeaxanthin. The antioxidant activity of spirulina was determined in water and crude carotenoid extracts by 2,2-diphenyl-1-picryhydrazyl (DPPH) scavenging assay, both extracts showed a significant free radical scavenging capacity. In addition, Nile tilapia fry (0.83 ± 0.01 g) was fed a vegetarian diet supplemented with different levels of spirulina for 12 weeks. The results revealed that the highest growth performance and nutrient utilization were recorded with 0.5% spirulina and the peak response determined at 0.63%-0.65% using polynomial second order regression. Also, the hemoglobin content improved in a quadratic regression model with the peak at 0.67% spirulina. Plasma total protein and lipid contents increased significantly with spirulina levels over 0.50%. Moreover, the aminopeptidase activities and glucose level decreased significantly with increasing spirulina levels. The current study recommended the supplementation of the Nile tilapia vegetarian diet with spirulina at levels of 0.63-0.65% for better growth performance and physiological status.

Carotenoids and Some Other Pigments from Fungi and Yeasts

Carotenoids are an essential group of compounds that may be obtained by microbiological synthesis. They are instrumental in various areas of industry, medicine, agriculture, and ecology. The increase of carotenoids' demand at the global market is now essential. At the moment, the production of natural carotenoids is more expensive than obtaining their synthetic forms, but several new approaches/directions on how to decrease this difference were developed during the last decades. This review briefly describes the information accumulated until now about the beneficial effects of carotenoids on human health protection, their possible application in the treatments of various diseases, and their use in the food and feed industry. This review also describes some issues that are linked with biotechnological production of fungal and yeasts carotenoids, as well as new approaches/directions to make their biotechnological production more efficient.

Yeast carotenoids: production and activity as antimicrobial biomolecule

Carotenoids are a large group of organic, pigmented, isoprenoid-type compounds that play biological activities in plants and microorganisms (yeasts, bacteria, and microalgae). Literature reported it as vitamin A precursors and antioxidant activity. Carotenoids also can act as antimicrobial agents and few reports showed quantitative measurements of Minimal Inhibitory Concentrations against different pathogens. In this sense, some carotenoids were added to medical-surgical materials. The demand for scale-up of different naturally obtained carotenoids has increased due to the concern about the detrimental health effects caused by synthetic molecules and antimicrobial resistance. In this review, we reported the variability in pigment production and culture conditions, extraction methods used in laboratory, and we discussed the antimicrobial activity carried out by these molecules and the promising acting as new molecules to be scaled-up to industry.

Microwave Hydrodiffusion and Gravity (MHG) Extraction from Different Raw Materials with Cosmetic Applications

Microwave hydrodiffusion and gravity (MHG) and ethanolic solid-liquid extraction were compared using selected plant sources. Their bioactive profile, color features, and proximate chemical characterization were determined. MHG extracts, commercial antioxidants, and three distinct types of thermal spring water were used in a sunscreen cream formulation. Their bioactive capacity, chemical and rheological properties were evaluated. MHG Cytisus scoparius flower extract provided the highest bioactive properties. Pleurotus ostreatus MHG liquor exhibited the highest total solid extraction yield. The Brassica rapa MHG sample stood out for its total protein content and its monosaccharide and oligosaccharide concentration. Quercus robur acorns divided into quarters supplied MHG extract with the lowest energy requirements, highest DPPH inhibition percentage, total lipid content and the highest enzyme inhibition. The chemical and bioactive capacities stability of the sunscreen creams elaborated with the selected MHG extracts and the thermal spring waters showed a similar behavior than the samples containing commercial antioxidants.