Microalgae-mediated biofixation as an innovative technology for flue gases towards carbon neutrality: A comprehensive review.

Microalgae-mediated industrial flue gas biofixation has been widely discussed as a clean alternative for greenhouse gas mitigation. Through photosynthetic processes, microalgae can fix carbon dioxide (CO2) and other compounds and can also be exploited to obtain high value-added products in a circular economy. One of the major limitations of this bioprocess is the high concentrations of CO2, sulfur oxides (SOx), and nitrogen oxides (NOx) in flue gases, according to the origin of the fuel, that can inhibit photosynthesis and reduce the process efficiency. To overcome these limitations, researchers have recently developed new technologies and enhanced process configurations, thereby increased productivity and CO2 removal rates. Overall, CO2 biofixation rates from flue gases by microalgae ranged from 72 mg L-1 d -1 to over 435 mg L-1 d-1, which were directly influenced by different factors, mainly the microalgae species and photobioreactor. Additionally, mixotrophic culture have shown potential in improving microalgae productivity. Progress in developing new reactor configurations, with pilot-scale implementations was observed, resulting in an increase in patents related to the subject and in the implementation of companies using combustion gases in microalgae culture. Advancements in microalgae-based green technologies for environmental impact mitigation have led to more efficient biotechnological processes and opened large-scale possibilities.

Fine resolution analysis of bacterial communities associated with Neochloris oleoabundans culture and insights into terpenes as contamination control agents.

Biological contamination is one of the main bottlenecks in microalgae production, reducing quality and productivity and sometimes leading to the complete loss of the cultures. Selecting terpenes can be a pathway toward eco-friendly contamination control in microalgae cultures. This work evaluated the presence of bacterial contaminants in N. oleoabundans cultures through HTS and 16 S analysis and their susceptibility to six natural terpenes (α-pinene, ß-pinene, limonene, trans-cinnamaldehyde, linalool, and eugenol). The principal phyla identified were Proteobacteria, Bacteroidetes, and Actinobacteria, and based on these data, 89 bacterial isolates of seven genera were obtained (36 Aureimonas sp., 27 Microbacterium sp., 5 Pseudomonas sp., 9 Bacillus sp., 14 Shinella sp., 1 Brevundimonas sp., and 1 Exiguobacterium sp.) at 25ºC in the presence of light. It was possible to observe that Beta-pinene 50 mg L- 1 only inhibited Bacillus sp. In contrast, Alpha-pinene, Linalool, and Trans-cinnamaldehyde, at a concentration of 6.25 mg L- 1 efficiently inhibited most isolates. The inhibition percentages found were 79-99%.

Simultaneous reuse and treatment of sugar-sweetened beverage wastes for citric acid production.

This study aimed to evaluate the feasibility of using sugar-sweetened beverages (SSB) for citric acid (CA) production and its impact on chemical oxygen demand (COD) of SSB. Five types of SSB were used as a carbon source for CA production by A. niger, and the COD of each SSB was measured before and after the bioprocess. Results showed that all tested SSB were suitable for CA production, with maximum yields ranging from 13.01 to 56.62 g L- 1. The COD was reduced from 53 to 75.64%, indicating that the bioprocess effectively treated SSB wastes. The use of SSB as a substrate for CA production provides an alternative to traditional feedstocks, such as sugarcane and beet molasses. The low-cost and high availability of SSB makes it an attractive option for CA production. Moreover, the study demonstrated the potential of the bioprocess to simultaneously treat and reuse SSB wastes, reducing the environmental impact of the beverage industry. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05761-9.

Bacillus subtilis natto as a potential probiotic in animal nutrition.

The growing global demand for animal products and processed meat has created a challenge for the livestock sector to enhance animal productivity without compromising product quality. The restriction of antibiotics in animal feeds as growth promoters makes the use of probiotics a natural and safe alternative to obtain functional foods that provide animal health and quality and to maintain food safety for consumers. To incorporate these additives into the diet, detailed studies are required, in which in vitro and in vivo assays are used to prove the efficacy and to ensure the safety of probiotic candidate strains. Studies on the use of Bacillus subtilis natto as a spore-forming probiotic bacterium in animal nutrition have shown no hazardous effects and have demonstrated the effectiveness of its use as a probiotic, mainly due to its proven antimicrobial, anti-inflammatory, antioxidant, enzymatic, and immunomodulatory activity. This review summarizes the recent scientific background on the probiotic effects of B. subtilis natto in animal nutrition. It focuses on its safety assessment, host-associated efficacy, and industrial requirements.

Influence of organic solvents in the extraction and purification of torularhodin from Sporobolomyces ruberrimus.

OBJECTIVE: This work aimed at evaluating the influence of organic solvents and stationary phases in the extraction with glass beads and chromatographic purification of carotenoids, especially torularhodin, from Sporobolomyces ruberrimus. RESULTS: The combinations of acetone:hexane (1:1 v/v) and acetone:ethyl ether (1:1 v/v) yielded 171.74 and 172.19 µg of total carotenoids.g of cells-1, respectively. The first blend resulted in the highest percent of cell lysis of 57.4%. Among different proportions of acetone:hexane, the 9:1 v/v mixture showed a significant difference (p < 0.05), resulting in a recovery of total carotenoids of 221.88 µg.g of cells-1. The purification of carotenoids was made by preparative chromatography and the yield of the silica-containing stationary phase was higher (24 µg torularhodin.g cells-1). The analyses of the purified fractions in thin layer chromatography and high performance liquid chromatography indicated that the purification of carotenoids, especially of torularhodin, was successfully performed. CONCLUSIONS: The combination of polar (acetone) and non-polar solvents (hexane) and the use of silica as stationary phase was efficient to recover and purify torularhodin from the intracellular pigments of Sporobolomyces ruberrimus.

Viruses in fermented foods: are they good or bad? Two sides of the same coin.

The emergence of Coronavirus disease 2019 as a global pandemic has increased popular concerns about diseases caused by viruses. Fermented foods containing high loads of viable fungi and bacteria are potential sources for virus contamination. The most common include viruses that infect bacteria (bacteriophage) and yeasts reported in fermented milks, sausages, vegetables, wine, sourdough, and cocoa beans. Recent molecular studies have also associated fermented foods as vehicles for pathogenic human viruses. Human noroviruses, rotavirus, and hepatitis virus have been identified in different fermented foods through multiple routes. No severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) virus or close members were found in fermented foods to date. However, the occurrence/persistence of other pathogenic viruses reveals a potential vulnerability of fermented foods to SARS-CoV-2 contamination. On the other side of the coin, some bacteriophages are being suggested for improving the fermentation process and food safety, as well as owing potential probiotic properties in modern fermented foods. This review will address the diversity and characteristics of viruses associated with fermented foods and what has been changed after a short introduction to the most common next-generation sequencing platforms. Also, the risk of SARS-CoV-2 transmission via fermented foods and preventive measures will be discussed.

Integrating microbial metagenomics and physicochemical parameters and a new perspective on starter culture for fine cocoa fermentation.

Cocoa beans used for chocolate production are fermented seeds of Theobroma cacao obtained by a natural fermentation process. The flavors and chemical compounds produced during the fermentation process make this step one of the most important in fine chocolate production. Herein, an integrative analysis of the variation of microbial community structure, using a shotgun metagenomics approach and associated physicochemical features, was performed during fermentation of fine cocoa beans. Samples of Forastero variety (FOR) and a mixture of two hybrids (PS1319 and CCN51) (MIX) from Bahia, Brazil, were analyzed at 7 different times. In the beginning (0 h), the structures of microbial communities were very different between FOR and MIX, reflecting the original plant-associated microbiomes. The highest change in microbial community structures occurred at the first 24 h of fermentation, with a marked increase in temperature and acetic acid concentration, and pH decrease. At 24-48 h both microbial community structures were quite homogenous regarding temperature, acetic acid, succinic acid, pH, soluble proteins and total phenols. During 72-96 h, the community structure resembles an acidic and warmer environment, prevailing few acetic acid bacteria. Taxonomic richness and abundance at 72-144 h exhibited significant correlation with temperature, reducing sugars, succinic, and acetic acids. Finally, we recommend that dominant microbial species of spontaneous fine cocoa fermentations should be considered as inoculum in accordance with the farm/region and GMP to maintain a differential organoleptic feature for production of fine chocolate. In our study, a starter inoculum composed of Acetobacter pausterianus and Hanseniaspora opuntiae strains is indicated.

Metagenomic analyses, isolation and characterization of endophytic bacteria associated with Eucalyptus urophylla BRS07-01 in vitro plants.

Eucalyptus is the main species for the forestry industry in Brazil. Biotechnology and, more recently, gene editing offer significant opportunities for rapid improvements in Eucalyptus breeding programs. However, the recalcitrance of Eucalyptus species to in vitro culture is also a major limitation for commercial deployment of biotechnology techniques in Eucalyptus improvement. We evaluated various clones of Eucalyptus urophylla for their in vitro regeneration potential identified a clone, BRS07-01, with considerably higher regeneration rate (85%) in organogenesis, and significantly higher than most works described in literature. Endophytic bacteria are widely reported to improve in vitro plant growth and development. Hence, we believe that inclusion of endophytic plant growth promoting bacteria enhanced was responsible for the improved plantlets growth and development of this clone under in vitro culture. Metagenomic analysis was performed to isolate and characterize the prominent endophytic bacteria on BRS07-01 leaf tissue in vitro micro-cultures, and evaluate their impact on plant growth promotion. The analysis revealed the presence of the phyla Firmicutes (35%), Proteobacteria (30%) and much smaller quantities of Actinobacteria, Bacteroidetes, Gemmatimonadetes, Crenarchaeota, Euryarchaeota and Acidobacteria. Of the thirty endophytic bacterial strains isolated, eleven produced indole-3-acetic acid. Two of the isolates were identified as Enterobacter sp. and Paenibacillus polymyxa, which are nitrogen-fixing and capable of phosphate and produce ammonium. These isolates also showed similar positive effects on the germination of common beans (Phaseolus spp.). The isolates will now be tested as a growth promoter in Eucalyptus in vitro cultures. Graphical abstract for the methodology using cultivation independent and dependent methodologies to investigate the endophytic bacteria community from in vitro Eucalyptus urophylla BRS07-01.

Sequential chemical and enzymatic pretreatment of palm empty fruit bunches for Candida pelliculosa bioethanol production.

Second-generation bioethanol production process was developed using pretreated empty fruit bunches (EFB). Consecutive acid/alkali EFB pretreatment was performed, first with HCl and then with NaOH with final washing steps for phenolic compounds elimination. Scanning electron microscopy images showed that EFB chemical treatments indeed attacked the cellulose fibers and removed the silica from surface pores. The optimization of enzymatic hydrolysis of EFB's cellulosic fraction was performed with 0.5%-4% v/v of Cellic® CTec2/Novozymes, different EFB concentrations (5%-15%, w/v), and hydrolysis time (6-72 H). Optimization essays were carried out in Erlenmeyer flasks and also in a 1 L stirred tank reactor. After enzymatic hydrolysis, a hydrolysate with 66 g/L of glucose was achieved with 2.2% (v/v) Cellic® CTec2, 15% (m/v) acid/alkaline pretreated EFB after 39 H of hydrolysis. A gain of 11.2% was then obtained in the 1 L stirred tank promoted by the agitation (72.2 g/L glucose). The hydrolysate was employed in bioethanol production by a new isolate Candida pelliculosa CCT 7734 in a separate hydrolysis and fermentation process reaching 16.6 and 23.0 g/L of bioethanol through batch and fed-batch operation, respectively. An integrated biorefinery process was developed for EFB processing chain.

The potential of plant systems to break the HIV-TB link.

Tuberculosis (TB) and human immunodeficiency virus (HIV) can place a major burden on healthcare systems and constitute the main challenges of diagnostic and therapeutic programmes. Infection with HIV is the most common cause of Mycobacterium tuberculosis (Mtb), which can accelerate the risk of latent TB reactivation by 20-fold. Similarly, TB is considered the most relevant factor predisposing individuals to HIV infection. Thus, both pathogens can augment one another in a synergetic manner, accelerating the failure of immunological functions and resulting in subsequent death in the absence of treatment. Synergistic approaches involving the treatment of HIV as a tool to combat TB and vice versa are thus required in regions with a high burden of HIV and TB infection. In this context, plant systems are considered a promising approach for combatting HIV and TB in a resource-limited setting because plant-made drugs can be produced efficiently and inexpensively in developing countries and could be shared by the available agricultural infrastructure without the expensive requirement needed for cold chain storage and transportation. Moreover, the use of natural products from medicinal plants can eliminate the concerns associated with antiretroviral therapy (ART) and anti-TB therapy (ATT), including drug interactions, drug-related toxicity and multidrug resistance. In this review, we highlight the potential of plant system as a promising approach for the production of relevant pharmaceuticals for HIV and TB treatment. However, in the cases of HIV and TB, none of the plant-made pharmaceuticals have been approved for clinical use. Limitations in reaching these goals are discussed.

L-lysine production improvement: a review of the state of the art and patent landscape focusing on strain development and fermentation technologies.

L-lysine is an essential amino acid used in various industrial sectors but mainly in food and animal feed. Intense research has been directed toward increasing its productivity. This literature review presents the state of the art and patent landscape of the industrial production of L-lysine, with a focus on the strain development and fermentation technologies, through geographic, social, and chronological analysis, using the text mining technique. The geographic analysis showed a greater tendency for countries with industrial plants with large production capacity to submit patents or publish articles, while the social analysis reflected the close relationship between educational units and companies. The technologies of each document were divided into optimization of fermentation parameters, conventional mutation, and genetic engineering. Corynebacterium glutamicum and Escherichia coli present the most attractive industrial phenotypes, and their cultivation occurs mainly in fed-batch processes with control parameters carefully selected to enhance metabolism. These strains are generally modified by conventional approaches (e.g., mutagenesis and selection of auxotrophic and/or regulatory mutants) or by genetic engineering technologies. The combination of both these approaches enables genomic breeding and the construction of strains with industrial potential, capable of accumulating more than 120 g/L of L-lysine. From the analysis of these approaches, we developed a descriptive flow of substrate uptake, amino acid metabolism, and mechanisms of excretion of a lysine-producing model cell. It is expected that the various mechanisms of L-lysine production, here shown and described, will become a guide that aids in increasing amino acid productivity without interfering with the strain stability.

Process parameters optimization to produce the recombinant protein CFP10 for the diagnosis of tuberculosis.

The aim of this study was to evaluate the parameters that affect the production of the recombinant 10 kDa culture filtrate protein (CFP10), a promising reagent of high specificity for intradermoreaction and other antigen-based methods used in the diagnosis of tuberculosis. Conditions of Escherichia coli growth temperature, induction temperature and IPTG-inducer concentration were evaluated in shake flasks and dissolved O2 concentrations of 15 and 30% were evaluated in a bioreactor. The process parameters defined on small scale were: growth temperature between 30 and 37 °C, induction temperature of 26 °C and IPTG concentration of 0.12 mM. The process conducted with 15% dissolved O2 presented a recombinant protein yield of 78.6 mg g-1 biomass and a proportion of recombinant protein (insoluble fraction) in relation to total insoluble protein of 72%, at the time of maximum productivity. The operation with 30% dissolved O2 resulted in lower recombinant protein yields of 62.9 mg g-1 biomass and 20% in relation to total insoluble protein, but in higher overall concentration in the culture broth (69.2 mg L-1versus 48.3 mg L-1). The protein identity was confirmed by mass spectrometry, showing high similarity to CFP10, 10 kDa of Mycobacterium tuberculosis H37Rv (score 95), and the purified antigen presented reactivity by the Western blotting assay.

Biological contamination and its chemical control in microalgal mass cultures.

Microalgae are versatile sources of bioproducts, a solution for many environmental problems. However, and despite its importance, one of the main problems in large-scale cultures-the presence of contaminants-is rarely systematically approached. Contamination, or the presence of undesirable organisms in a culture, is deleterious for the culture and frequently leads to culture crashes. To avoid contamination, closed systems can be used; however, for very large-scale open systems, contamination is unavoidable and remediation procedures are necessary-ranging from physicochemical treatment to addition of biocidal substances. In all cases, early detection and culture monitoring are paramount. This article describes the biological contaminants, contamination mechanisms, and control systems used in open and closed cultures, discussing the latest advances and techniques in the area. It also discusses the complex interactions of algae with other microorganisms that can be expected in cultivation systems.

Biological evaluation of mimetic peptides as active molecules for a new and simple skin test in an animal model.

A skin test is a widely used tool in diagnostic evaluations to investigate cutaneous leishmaniases (CL). The actual antigen (Montenegro skin test [MST] antigen) presents some difficulties that pertain to its manufacturing and validation. To contribute to overcoming this problem, we propose the application of new-generation molecules that are based on skin antigen tests. These antigens were obtained through biotechnology pathways by manufacturing synthetic mimetic peptides. Three peptides, which were selected by phage display, were tested as skin test antigens in an animal model (Cavia porcellus) that was immunized with Leishmania amazonensis or Leishmania braziliensis. The peptide antigens, individually (PA1, PA2, PA3) or in a mix (PAMix), promoted induration reactions at 48 and 72 h after the test was performed. The indurations varied from 0.5 to 0.7 cm. In the animals immunized with L. amazonensis, the PA3 antigen showed better results than the standard MST antigen. In animals immunized with L. braziliensis, two peptide antigens (PA2 and PAMix) promoted induration reactions for a longer period of time than the standard MST antigen. These results validate our hypothesis that peptides could be used as antigens in skin tests and may replace the current antigen for CL diagnosis.

High-Throughput rRNA Gene Sequencing Reveals Highand Complex Bacterial Diversity Associated withBrazilian Coffee Bean Fermentation.

Coffee bean fermentation is a spontaneous, on-farm process involving the action of different microbial groups, including bacteria and fungi. In this study, high-throughput sequencing approach was employed to study the diversity and dynamics of bacteria associated with Brazilian coffee bean fermentation. The total DNA from fermenting coffee samples was extracted at different time points, and the 16S rRNA gene with segments around the V4 variable region was sequenced by Illumina high-throughput platform. Using this approach, the presence of over eighty bacterial genera was determined, many of which have been detected for the first time during coffee bean fermentation, including Fructobacillus, Pseudonocardia, Pedobacter, Sphingomonas and Hymenobacter. The presence of Fructobacillus suggests an influence of these bacteria on fructose metabolism during coffee fermentation. Temporal analysis showed a strong dominance of lactic acid bacteria with over 97% of read sequences at the end of fermentation, mainly represented by the Leuconostoc and Lactococcus. Metabolism of lactic acid bacteria was associated with the high formation of lactic acid during fermentation, as determined by HPLC analysis. The results reported in this study confirm the underestimation of bacterial diversity associated with coffee fermentation. New microbial groups reported in this study may be explored as functional starter cultures for on-farm coffee processing.

Effects of Cordyceps sinensis on macrophage function in high-fat diet fed rats and its anti-proliferative effects on IMR-32 human neuroblastoma cells.

Macrophages have been considered an elusive yet emerging therapeutic target in tumor development since they are an important component in tumor microenvironment. The purpose of the present study was to evaluate the effect of C. sinensis on macrophage function (a component of tumor microenvironment which can alter the virulence of cancer) in high-fat diet fed rats. IMR-32 human neuroblastoma cell cytotoxicity was also investigated. The following parameters were observed to evaluate macrophage function: superoxide anion, hydrogen peroxide, nitric oxide, lysosomal volume and phagocytic capacity. High fat diet (HFD) plus C. sinensis supplementation promoted a decreased superoxide anion and hydrogen peroxide levels as well as lysosomal volume and phagocytic capacity. Nitric oxide was increased in the same group. In summary, C. sinensis offered an important anti-tumoral perspective from the standpoint of the tumor microenvironment and in vitro IMR-32 cytotoxicity.

Technological trends and market perspectives for production of microbial oils rich in omega-3.

In recent years, foods that contain omega-3 lipids have emerged as important promoters of human health. These lipids are essential for the functional development of the brain and retina, and reduction of the risk of cardiovascular and Alzheimer's diseases. The global market for omega-3 production, particularly docosahexaenoic acid (DHA), saw a large expansion in the last decade due to the increasing use of this lipid as an important component of infant food formulae and supplements. The production of omega-3 lipids from fish and vegetable oil sources has some drawbacks, such as complex purification procedures, unwanted contamination by marine pollutants, reduction or even extinction of several species of fish, and aspects related to sustainability. A promising alternative system for the production of omega-3 lipids is from microbial metabolism of yeast, fungi, or microalgae. The aim of this review is to discuss the various omega-3 sources in the context of the global demand and market potential for these bioactive compounds. To summarize, it is clear that fish and vegetable oil sources will not be sufficient to meet the future needs of the world population. The biotechnological production of single-cell oil comes as a sustainable alternative capable of supplementing the global demand for omega-3, causing less environmental impact.

Microbial ecology and starter culture technology in coffee processing.

Coffee has been for decades the most commercialized food product and most widely consumed beverage in the world, with over 600 billion cups served per year. Before coffee cherries can be traded and processed into a final industrial product, they have to undergo postharvest processing on farms, which have a direct impact on the cost and quality of a coffee. Three different methods can be used for transforming the coffee cherries into beans, known as wet, dry, and semi-dry methods. In all these processing methods, a spontaneous fermentation is carried out in order to eliminate any mucilage still stuck to the beans and helps improve beverage flavor by microbial metabolites. The microorganisms responsible for the fermentation (e.g., yeasts and lactic acid bacteria) can play a number of roles, such as degradation of mucilage (pectinolytic activity), inhibition of mycotoxin-producing fungi growth, and production of flavor-active components. The use of starter cultures (mainly yeast strains) has emerged in recent years as a promising alternative to control the fermentation process and to promote quality development of coffee product. However, scarce information is still available about the effects of controlled starter cultures in coffee fermentation performance and bean quality, making it impossible to use this technology in actual field conditions. A broader knowledge about the ecology, biochemistry, and molecular biology could facilitate the understanding and application of starter cultures for coffee fermentation process. This review provides a comprehensive coverage of these issues, while pointing out new directions for exploiting starter cultures in coffee processing.

Downstream process development in biotechnological itaconic acid manufacturing.

Itaconic acid is a promising chemical that has a wide range of applications and can be obtained in large scale using fermentation processes. One of the most important uses of this biomonomer is the environmentally sustainable production of biopolymers. Separation of itaconic acid from the fermented broth has a considerable impact in the total production cost. Therefore, optimization and high efficiency downstream processes are technological challenges to make biorefineries sustainable and economically viable. This review describes the current state of the art in recovery and purification for itaconic acid production via bioprocesses. Previous studies on the separation of itaconic acid relying on operations such as crystallization, precipitation, extraction, electrodialysis, diafiltration, pertraction, and adsorption. Although crystallization is a typical method of itaconic acid separation from fermented broth, other methods such as membrane separation and reactive extraction are promising as a recovery steps coupled to the fermentation, potentially enhancing the overall process yield. Another approach is adsorption in fixed bed columns, which efficiently separates itaconic acid. Despite recent advances in separation and recovery methods, there is still space for improvement in IA recovery and purification.

Microbiological, biochemical, and functional aspects of sugary kefir fermentation - A review.

Sugary kefir beverage is produce by fermenting raw sugar solution with kefir grains, the latter consisting of polysaccharide and microorganisms. This beverage, with great consumption in countries such as USA, Japan, France, and Brazil, represents a promising market to functional cultured drinks. This paper reviews the microbial diversity and interaction, kinetics, safety, and bioactivities of sugary kefir fermentation. The literature reviewed here demonstrates that sugary kefir possesses a similar microbial association relative to traditional milk kefir fermentation, especially among lactic acid bacteria and yeast species, such as Lactobacillus, Leuconostoc, Kluyveromyces, Pichia, and Saccharomyces. However, a selective pressure at species level is generally observed, as, for example, the stimulation of Saccharomyces species metabolism, leading to a high content of alcohol in the final product. This also seems to stimulate the growth of acetic acid bacteria that benefit of increased ethanol production to acetic acid metabolism. Existing reports have suggested important bioactivities associated with sugary kefir beverage consumption, such as antimicrobial, antiedematogenic, anti-inflammatory, antioxidant, cicatrizing, and healing activities. Other alternative non-dairy substrates, such as fruits, vegetables, and molasses, have also been tested for adaptation of kefir grains and production of functional beverages with distinct sensory characteristics. This diversification is of crucial importance for the production of new probiotic products to provide people with special needs (lactose intolerance) and vegan consumers.