Yeast Fermentation Process Research Articles

Physical Modifications of Kombucha‐Derived Bacterial Nanocellulose: Toward a Functional Bionanocomposite Platform

AbstractSustainable functionalization of bacterial cellulose for cost‐effective bionanocomposites with desired properties has received growing attention in recent years. This article presents the results of work aimed at obtaining bionanocomposite materials based on bacterial cellulose, a natural and eco‐friendly material. Bacterial cellulose obtained from the Kombucha symbiotic culture of bacteria and yeast (SCOBY) fermentation process is functionalized by embedding with diatom frustules, silver nanoparticles (AgNPs), and poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS). The effects of functionalization on mechanical, optical, plasmonic, electrical, chemiluminescent, and antimicrobial properties are evaluated. Morphological characteristics of the nanocomposites are studied using electron microscopy. Addition of diatom frustules introduced into the SCOBY culture media results in bionanocomposite materials with enhanced tensile strength and increased ultraviolet (UV) blockage properties. In situ functionalization of bacterial cellulose with AgNPs tunes plasmonic and chemiluminescent properties, revealing the biosensing potential of the material. Modified bacterial cellulose shows antimicrobial activity in experiments with gram‐positive and gram‐negative bacteria. Dual functionalization of bacterial cellulose with PEDOT:PSS and AgNPs results in improved electrical conductivity of the bionanocomposite. Overall, bottom‐up physical functionalization approaches and the resulting bionanocomposite materials will open up new opportunities for the low‐cost production of green materials and contribute to the development of a sustainable economy.

Utilizing deep ocean water in yeast fermentation for enhanced mineral-rich biomass production and fermentative regulation by proteomics modulation

Deep Ocean Water (DOW) is rich in minerals and serves as a natural source of nutrients. However, due to the inorganic nature of these minerals, cultivating yeast in DOW could aid in the fermentation process, and simultaneously, the yeast can assimilate the minerals from DOW, resulting in a mineral-enriched yeast biomass. Focusing on three DOW sources off the eastern coast of Taiwan (TT-1, HL-1, HL-2), we fermented various yeast strains of Saccharomyces cerevisiae. Therefore, this study investigates the effects of DOW on yeast growth, alcohol dehydrogenase activity, and the biological absorption of mineral ions by the yeast. Additionally, this research employs two-dimensional electrophoresis techniques to examine how the absorbed minerals influence the regulation of yeast proteins, thereby affecting biomass and metabolism. In the result, S. cerevisiae BCRC 21689 demonstrated a remarkable ability to bio-absorb minerals such as magnesium, calcium, potassium, and zinc from DOW, enhancing its growth and fermentation performance. Proteomic analysis revealed significant shifts in the expression of 21 proteins related to glycolytic and energy metabolism, alcohol metabolism, and growth regulation, all influenced by DOW's mineral-rich environment. This indicates that DOW's mineral content is a key factor in upregulating essential enzymes in glycolytic metabolism and alcohol dehydrogenase. An increase in proteins involved in synthesis and folding processes was also observed, leading to a substantial increase in yeast biomass. This study underscores the potential of DOW as a natural enhancer in yeast fermentation processes, enriching the yeast with diverse minerals and modulating proteomic expression to optimize yeast growth and fermentation.

Fermentation Process Effects on Fermented McIntosh Apple Ciders

This research is the first study of McIntosh apple cider fermentation using different must treatments. The must materials included standard pressed juice, the common cider fermentation material, mash, direct from the apple shredder both with and without pectinase additions, and finally, pomace. These four treatments caused multiple differences from the standard hard ciders from juice, starting with the apple must characteristics, following through the yeast fermentation processes, and carried into the final ciders. Initial apple musts had different sugar content, pH, acids, total phenolics, and antioxidant activities. Although juice contained more total phenolics and had more antioxidant capabilities, it contained lower levels of yeast assimilable nitrogen. The sugar consumption dynamic changes had a differential dynamic trend but did not alter the capacity for complete apple cider fermentation. From the fermentation color dynamic changes, it indicated that must materials would have effects on color-changing amplitudes. Juice treatment had the largest changes from the must. Pomace and mash with pectinase had fewer color changes in multiple color values (L*, a*, b*). The mono phenolics in the final cider indicated that pomace ferments contained the least hydroxycinnamates but a similar amount of total flavanols as juice-fermented ciders. Cider from the juice contained the least flavonols, whereas the mash, both with and without pectinase treatments, had the largest amount of flavonols. This work will provide some applicable information for apple cider fermentation from the apple wastes in the cider industry.

Kilo-Scale GMP Synthesis of Renewable Semisynthetic Vaccine-Grade Squalene.

Emulsions of the triterpene squalene ((6E,10E,14E,18E)-2,6,10,15,19,23-hexamethyltetracosa-2,6,10,14,18,22-hexaene, CAS 111-02-4) have been used as adjuvants in influenza vaccines since the 1990s. Traditionally sourced from shark liver oil, the overfishing of sharks and concomitant reduction in the oceanic shark population raises sustainability issues for vaccine adjuvant grade squalene. We report a semisynthetic route to squalene meeting current pharmacopeial specifications for use in vaccines that leverages the ready availability of trans-β-farnesene ((6E)-7,11-dimethyl-3-methylene-1,6,10-dodecatriene, CAS 18794-84-8), manufactured from sustainable sugarcane via a yeast fermentation process. The scalability of the proposed route was verified by a kilo-scale GMP synthesis. We also report data demonstrating the synthesized semi-synthetic squalene's physical stability and biological activity when used in a vaccine adjuvant formulation.

A novel sophorolipids extraction method by yeast fermentation process for enhanced skin efficacy.

Oriental herbs have been used as medicines in the folk remedy for their numerous phytochemicals and bioactivities. In this study, we have selected five Korean traditional medical herbs and applied bio conversion extraction technology, named it as Bioconversion Oji complex, to identify phytochemicals and evaluate skin related efficacies. The process of two-step bio conversion was sequentially conducted. The first step of fermentation was to produce biosurfactants using macadamia seed oil with Candida bombicola, and then five natural plants were added to carry out the main fermentation. To evaluate skin improvement efficacy of Bioconversion Oji complex, in vitro and in vivo studies were conducted. We studied HaCaT cells cultured to assess viability, skin anti-inflammatory, moisturizing and barrier improvement-related mRNA expression. For efficacy study, 21 participants were tested evaluating anti-inflammatory, skin moisturizing and skin barrier improving effects of Bioconversion Oji complex compared to Water extraction of Oji (placebo) for the 4 weeks test period. The application of bioconversion technology highly increased the content of amino acids and lipids within Bioconversion Oji complex, and 23 flavonoids were also identified. Bioconversion Oji complex was found to be non-toxic and showed significant effects in all parameters tested, including anti-inflammation, skin moisture, and skin barrier in both in vitro and in clinical studies. Bioconversion Oji complex has demonstrated skin-friendly properties with significant beneficial effects on anti-inflammatory, skin hydration and barrier function properties. This study provides evidence for the use of Bioconversion Oji complex as an active ingredient in cosmetics and skincare products.

A Delta-Omicron Bivalent Subunit Vaccine Elicited Antibody Responses in Mice against Both Ancestral and Variant Strains of SARS-CoV-2.

Continued mutation of the SARS-CoV-2 genome has led to multiple waves of COVID-19 infections, and new variants have continued to emerge and dominate. The emergence of Omicron and its subvariants has substantially increased the infectivity of SARS-CoV-2. RBD genes of the wild-type SARS-CoV-2 strain and the Delta, Omicron BA.1 and Omicron BA.2 variants were used to construct plasmids and express the proteins in glycoengineered Pichia pastoris. A stable 4 L-scale yeast fermentation and purification process was established to obtain high-purity RBD proteins with a complex glycoform N-glycosyl structure that was fucose-free. The RBD glycoproteins were combined with two adjuvants, Al(OH)3 and CpG, which mitigated the typical disadvantage of low immunogenicity associated with recombinant subunit vaccines. To improve the broad-spectrum antiviral activity of the candidate vaccine, Delta RBD proteins were mixed with BA.2 RBD proteins at a ratio of 1:1 and then combined with two adjuvants-Al(OH)3 and CpG-to prepare a bivalent vaccine. The bivalent vaccine effectively induced mice to produce pseudovirus-neutralizing antibodies against SARS-CoV-2 variants, Delta, Beta, and Omicron sublineages BA.1, BA.2, BA.5. The bivalent vaccine could neutralize the authentic wild-type SARS-CoV-2 strain, Delta, BA.1.1, BA.2.2, BA2.3, and BA.2.12.1 viruses, providing a new approach for improving population immunity and delivering broad-spectrum protection under the current epidemic conditions.

Biomass conversion through optimization of cellulase from Chryseobacterium junjuense Bp17 and their utility in bioethanol production

The search for economically viable and less laborous strategy for bioethanol production has increased globally in this quest bacterial cellulase treated biomass has been promising. Potential bacterium isolated from the forest soil near Bandipur of Karnataka, India exploiting its cellulolytic activity on the CMC agar medium. Molecular identification and characterization of isolate Bp17 revealed as Chryseobacterium junjuense Bp17. An optimization study, enhance the yield of the enzyme through varying parameters such as time, temperature, and pH. Enzymatic assays like β 1, 4 endoglucanase (148.55 U/ml), β 1, 4 exoglucanase (37.21 U/ml), and β glucosidase (42.21 U/ml) exhibit the enzyme activity. Endo, exo and β-glucosidase activities of hydrolyzed biomass broth like coconut husk; 212.88 ± 1.24 U/ml, 151.65 ± 1.24 U/ml and 176.63 ± 1.24 U/ml, rice bran; 223.72 ± 1.42 U/ml, 112.88 ± 1.42 U/ml and 133.43 ± 1.42 U/ml, Pongamia leaves; 389.69 ± 2.54 U/ml, 205.92 ± 2.54 and 187.99 ± 2.54 U/ml, and wood waste; 196.86 ± 0.2 U/ml, 138.90 ± 0.2 U/ml and 168.84 ± 0.2 U/ml, respectively. Hydrolyzed and control biomass differences analyzed through Scanning electron microscope (SEM), Energy dispersive X-ray (EDX), and Fourier transform infrared (FTIR) spectroscopy. Zymography reveals the activity and molecular weight of cellulolytic enzymes (40-130 KB). Hydrolyzed broth filtrate produced from biomass used as crude enzyme and further used for bioethanol production through the yeast fermentation process.

Preparation of Taraxacum kok-saghyz Rubber and Biofuel Ethanol Simultaneously by the Yeast Fermentation Process.

Taraxacum kok-saghyz(TKS) rubber is considered the most ideal alternative source of natural rubber (NR). Extracting rubber from TKS with high quality, low cost, and low pollution is the basis of commercial development. The TKS roots were subjected to morphological observation and detailed compositional analysis. Scanning electron microscopy (SEM) images confirm that rubber filaments are physically entangled with plant tissues due to differences in molecular polarity. Compared with the traditional solvent TKS rubber extraction process, a new rubber extraction process developed in this study, namely, the microbial extraction (″ME″) process, is less harmful to the environment and lower in cost. The ″ME″ process is divided into three steps: dilute acid pretreatment process, enzyme degradation process, and fermentation process. After each step is completed, the purity of TKS rubber will gradually increase from 84.8% to 93.8 to 95.5%. The TKS rubber finally obtained fully meets the requirements of the traditional rubber industry, especially the tire industry. Besides, the yield of biofuel ethanol, a by-product of cellulose fermentation, reaches 2.05 g/100 g of TKS roots (dry weight), which can effectively reduce the production cost of TKS rubber. In the rubber extraction process, microorganisms have little effect on the quality of TKS rubber. The results show that the molecular weight and chemical structure of TKS rubber is very close to NR, so the ″ME″ process can be used as a new method for large-scale extraction of TKS rubber.

Study of Sulphides Production Affecting the Fermentation Process of the Lager Beer

In the lager brewing production process, volatile sulphides such as sulphur dioxide, hydrogen sulphide, thiols and thioesters are produced by yeast metabolism during the fermentation of lager beer. Fluctuations in malt raw materials, yeast strain characteristics and fermentation process parameter adjustments can all have an impact on sulphides, and the concentration of sulphides in finished beer can have a negative impact on the sensory tasting of lager beer. This study investigated the fermentation of sulphides in lager beer under the conditions of dissolved wort oxygen, yeast recovery, fermentation temperature and pressure, and the results showed that the longer the yeast growth time, the later the fermentation of sulphur dioxide and the lower the sulphur dioxide content in the final beer by 10mg/L. The longer the yeast recovery days, the higher the fermentation of sulphur dioxide and hydrogen sulphide. The higher the content, the higher the fermentation temperature of the lager and the faster the fermentation rate, which favours a low sulphur dioxide content at the end of the main fermentation.

Multi-Population Genetic Algorithm and Cuckoo Search Hybrid Technique for Parameter Identification of Fermentation Process Models

In this paper, a new hybrid MpGA-CS is elaborated between multi-population genetic algorithm (MpGA) and cuckoo search (CS) metaheuristic. Developed MpGA-CS has been adapted and tested consequently for modelling of bacteria and yeast fermentation processes (FP), due to their great impact on different industrial areas. In parallel, classic MpGA, classic CS, and a new hybrid MpGA-CS have been separately applied for parameter identification of E. coli and S. cerevisiae FP models. For completeness, the newly elaborated MpGA-CS has been compared with two additional nature-inspired algorithms; namely, artificial bee colony algorithm (ABC) and water cycle algorithm (WCA). The comparison has been carried out based on numerical and statistical tests, such as ANOVA, Friedman, and Wilcoxon tests. The obtained results show that the hybrid metaheuristic MpGA-CS, presented herein for the first time, has been distinguished as the most reliable among the investigated algorithms to further save computational resources.

Semi−Supervised Hybrid Modeling of the Yeast Fermentation Process

This study focuses on modeling the yeast fermentation process using the hybrid modeling method. To improve the prediction accuracy of the model and reduce the model training time, this paper presents a semi−supervised hybrid modeling method based on an extreme learning machine for the yeast fermentation process. The hybrid model is composed of the mechanism model and the residual model. The residual model is built from the residuals between the real yeast fermentation process and the mechanism model. The residual model is used in parallel with the mechanism model. Considering that the residuals might be related to the inaccurate parameters or structure of the process, the mechanism model output is taken as unlabeled data, and the suitable inputs are selected based on Pearson’s maximum correlation and minimum redundancy criterion (RRPC). Meanwhile, an extreme learning machine is employed to improve the model’s training speed while maintaining the model’s prediction accuracy. Consequently, the proposal proved its efficacy through simulation.

Bluestem pursues chemical fermentation

Bluestem Biosciences, a synthetic biology start-up, has raised $5 million in seed financing to pursue the production of chemicals via anaerobic fermentation. The company told the trade group Bio Nebraska it plans to license yeast strains and fermentation processes to companies that own fermentation infrastructure. Bluestem will use computational tools to develop a product pipeline. The company’s team includes alumni from synthetic biology companies such as Ginkgo Bioworks, Zymergen, and Amyris.

Production of naturally flavoured and carbonated beverages using Williopsis saturnus yeast and cold fermentation process

This study was carried out to develop a new functional fermented beverage that combines both the functional composition of grape (Tarsus beyazi) juice and metabolic products of the yeast Williopsis saturnus. For this reason, two trials were conducted. First, the effect of different inoculation ratios and low fermentation temperatures at different times was examined. In naturally flavoured beverages, there was generally a decrease in total phenolic substance, antioxidant activity and total flavonoid amount with increasing fermentation time and inoculation ratio. The panellists chose b-15d (1 × 106 cells/mL W. saturnus yeast addition, 15 days fermentation) and then c-15d (1 × 107 cells/mL W. saturnus yeast addition, 15 days fermentation) the most out of different beverages produced. Fermentation performed with yeasts inoculated at the rate of 1 × 106 and 1 × 107 cells/mL for 15 days was selected for the second trials based on both general and sensory analyses. For this reason, these beverages, which were most preferred by the panellists, were re-manufactured and naturally flavoured carbonated beverages were produced by adding CO2 with the post-mix method. Brix, sucrose, glucose and fructose values were determined in lower amounts in natural flavoured carbonated beverages compared to grape juice, which is given importance by consumers. As in naturally flavoured beverages, carbonated beverages also decreased in total phenolic substance, antioxidant activity and total flavonoid amount with increasing fermentation time. In addition, the c-15d natural flavoured carbonated beverage (1 × 107 cells/mL W. saturnus yeast addition, 15 days fermentation) was more favoured by the panellists than the commercially purchased carbonated beverage. The results reported here are considered to be a good starting point for the development of new naturally flavoured and/or carbonated fermented beverages from the under-consumed grape.

Study of yeast fermentation process in the inter-disciplinary project

Study of yeast fermentation process in the inter-disciplinary project

Characterization of the de-oiled yeast biomass for plausible value mapping in a biorefinery perspective

Oleaginous yeast fermentation process has gained attention for yeast single cell oil production. However, after lipid extraction, the leftover de-oiled yeast biomass has not been investigated in detail for its suitability for thermochemical conversion. To understand the structural and morphological changes, the comparative characterization of yeast and de-oiled yeast biomass before and post lipid extraction is necessary. The present study investigates the characteristics of an oleaginous yeast Rhodotorula mucilaginosa IIPL32′s de-oiled biomass for its potential utilization. FTIR, XRD, SEM, EDX, XRF, and TGA analysis were performed to understand the biomass properties. Increased surface area and structural changes were observed in de-oiled yeast biomass with an increase in crystallinity, indicating chitosan availability. Maximum thermal degradation temperature was reduced to 260 °C for de-oiled yeast biomass from 300 °C for dried yeast after lipid extraction. The findings favored de-oiled yeast biomass for multiple applications that merit further detailed investigation with different thermochemical interventions.

Immune activation of Bio-Germanium in a randomized, double-blind, placebo-controlled clinical trial with 130 human subjects: Therapeutic opportunities from new insights.

[NCT03677921]; www.clinicaltrials.gov [KCT0002726]; https://cris.nih.go.kr.

Online monitoring of the morphology of an industrial sugarcane biofuel yeast strain via in situ microscopy

In industrial yeast fermentation processes, single-cell yeast suspensions are usually preferable to cells in aggregates, as single cells exhibit a larger contact area with the nutrient medium, which in many cases helps optimize the process. In addition to affecting fermentation time and efficiency, cell aggregates (e.g., pseudohyphal yeast morphology) may also impair centrifugation systems, one of the most expensive and complex steps of the production process that involves the recovery of yeast cells for subsequent fermentation cycles. To date, no standard technique allows for a systematic diagnosis of yeast morphology in real time during sugarcane biofuel fermentation. Accordingly, we investigate an in situ microscope (ISM) for online monitoring of the density and morphology of an industrial Saccharomyces cerevisiae strain widely used in Brazilian distilleries (PE-2). During batch and repeated batch sugarcane molasses fermentation, the instrument revealed single cells, budding yeast cells, and pseudohyphae, all in a variety of sizes and shapes. The ISM image analysis indicated that the volume of single yeast cells increased by roughly 40% over the lag phase before budding and remained approximately constant thereafter. Pseudohyphae with three and more cells appeared mostly during the stationary phase. Cooling problems were simulated by raising the temperature from 33 to 45 °C. During this thermal stress, single cells as well as budding cells and pseudohyphae forming cells became smaller and exhibited intracellular inhomogeneities. From these results, we conclude that an ISM is a useful tool for monitoring yeast morphology during sugarcane fermentation. Atypical morphologies can be detected early and be used as an automatic warning system.

Adaptive Laboratory Evolution and Reverse Engineering of Single-Vitamin Prototrophies in Saccharomyces cerevisiae.

Quantitative physiological studies on Saccharomyces cerevisiae commonly use synthetic media (SM) that contain a set of water-soluble growth factors that, based on their roles in human nutrition, are referred to as B vitamins. Previous work demonstrated that in S. cerevisiae CEN.PK113-7D, requirements for biotin were eliminated by laboratory evolution. In the present study, this laboratory strain was shown to exhibit suboptimal specific growth rates when either inositol, nicotinic acid, pyridoxine, pantothenic acid, para-aminobenzoic acid (pABA), or thiamine was omitted from SM. Subsequently, this strain was evolved in parallel serial-transfer experiments for fast aerobic growth on glucose in the absence of individual B vitamins. In all evolution lines, specific growth rates reached at least 90% of the growth rate observed in SM supplemented with a complete B vitamin mixture. Fast growth was already observed after a few transfers on SM without myo-inositol, nicotinic acid, or pABA. Reaching similar results in SM lacking thiamine, pyridoxine, or pantothenate required more than 300 generations of selective growth. The genomes of evolved single-colony isolates were resequenced, and for each B vitamin, a subset of non-synonymous mutations associated with fast vitamin-independent growth was selected. These mutations were introduced in a non-evolved reference strain using CRISPR/Cas9-based genome editing. For each B vitamin, the introduction of a small number of mutations sufficed to achieve a substantially increased specific growth rate in non-supplemented SM that represented at least 87% of the specific growth rate observed in fully supplemented complete SM.IMPORTANCE Many strains of Saccharomyces cerevisiae, a popular platform organism in industrial biotechnology, carry the genetic information required for synthesis of biotin, thiamine, pyridoxine, para-aminobenzoic acid, pantothenic acid, nicotinic acid, and inositol. However, omission of these B vitamins typically leads to suboptimal growth. This study demonstrates that, for each individual B vitamin, it is possible to achieve fast vitamin-independent growth by adaptive laboratory evolution (ALE). Identification of mutations responsible for these fast-growing phenotypes by whole-genome sequencing and reverse engineering showed that, for each compound, a small number of mutations sufficed to achieve fast growth in its absence. These results form an important first step toward development of S. cerevisiae strains that exhibit fast growth on inexpensive, fully supplemented mineral media that only require complementation with a carbon source, thereby reducing costs, complexity, and contamination risks in industrial yeast fermentation processes.

Monitoring yeast fermentations by nonlinear infrared technology and chemometrics-understanding process correlations and indirect predictions.

Fermentation processes are still compromised by a lack of monitoring strategies providing integrated process data online, ensuring process understanding, control, and thus, optimal reactor efficiency. The crucial demand for online monitoring strategies, not only encouraged by the PAT initiative but also motivated by modern paradigms such as circular economy and sustainability, has driven research and industry to provide "next-generation process technology": in other words, technology tailored toward industrial needs. Mid-infrared (MIR) spectroscopy as such is superior to near-infrared (NIR) spectroscopy since it provides significantly enhanced selectivity. However, due to high costs and a lack of instrumental robustness, MIR spectroscopy is outcompeted by NIR when it comes to industrial application. The lack of chemometric expertise, model understanding, and practical guidance might add to the slow acceptance of industrial MIR application. This work demonstrates the use of novel MIR, so-called non-linear infrared (NLIR) technology and the importance of model understanding, exemplarily investigated on a lab-scale yeast fermentation process. The six analytes glucose, ethanol, glycerol, acetate, ammonium, and phosphate were modeled by partial least squares (PLS) based on spectral data, demonstrating the potential of the novel technology facilitating online data acquisition and the necessity of investigating indirect predictions. KEY POINTS: • NLIR spectra were acquired online during a yeast fermentation process • PLS models were constructed for six components based on uncorrelated samples • Glucose, ethanol, ammonium, and phosphates were modeled with errors of less than 15% • Acetate and glycerol were shown to rely on indirect predictions.

Differential Analysis of Proteins Involved in Ester Metabolism in two Saccharomyces cerevisiae Strains during the Second Fermentation in Sparkling Wine Elaboration.

The aromatic metabolites derived from yeast metabolism determine the characteristics of aroma and taste in wines, so they are considered of great industrial interest. Volatile esters represent the most important group and therefore, their presence is extremely important for the flavor profile of the wine. In this work, we use and compare two Saccharomyces cerevisiae yeast strains: P29, typical of sparkling wines resulting of second fermentation in a closed bottle; G1, a flor yeast responsible for the biological aging of Sherry wines. We aimed to analyze and compare the effect of endogenous CO2 overpressure on esters metabolism with the proteins related in these yeast strains, to understand the yeast fermentation process in sparkling wines. For this purpose, protein identification was carried out using the OFFGEL fractionator and the LTQ Orbitrap, following the detection and quantification of esters with gas chromatograph coupled to flame ionization detector (GC-FID) and stir-bar sorptive extraction, followed by thermal desorption and gas chromatography-mass spectrometry (SBSE-TD-GC-MS). Six acetate esters, fourteen ethyl esters, and five proteins involved in esters metabolism were identified. Moreover, significant correlations were established between esters and proteins. Both strains showed similar behavior. According to these results, the use of this flor yeast may be proposed for the sparkling wine production and enhance the diversity and the typicity of sparkling wine yeasts.