Ultrasound-assisted Fermentation Research Articles

Metabolic responses of kombucha consortium fermentation upon ultrasound-processing

This study investigated the effect of ultrasound-assisted fermentation on the metabolic responses of traditional and mango-flavored Kombucha fermentation. The results revealed significant differences in the sugar consumption kinetics of sonicated kombucha. Sucrose consumption over 9 days of fermentation (F1) was higher for control than US-processed kombucha. During the second fermentation (F2), ultrasound processing increased the rates of sucrose consumption as the US processing time increased. US15 increases sucrose consumption by 19 %. Ultrasound favored a higher yield of gluconic, propionic, and isobutyric acids than non-processed kombucha (control) and important changes in the kombucha bioactive compounds profile. Gluconic acid continuously increased to a maximum of 6.74 g/L on D12 (F2) in US15 kombucha compared to 4.17 g/L in non-processed one. The ethanol content was below 0.5 g/L for the sonicated kombucha, reaching its maximum of 0.46 g/L for US7 and 0.25 g/L for US15 kombucha after 28 days of refrigerated storage. Ultrasound-assisted fermentation may cause attenuation of kombucha microbiota and changes in the cellulose fiber, promoting modulation of kombucha consortium metabolism. This study's findings help to develop kombuchas with higher bioactive potential and contribute to optimizing the kombucha fermentation process.

Porphyrin and pH sensitive dye-based colorimetric sensor array coupled chemometrics for dynamic monitoring of tea quality during ultrasound-assisted fermentation

In current work, the response surface methodology using Box-Behnken design was initially used to optimize the fermentation conditions of green tea via consumption rate of tea polyphenol (CROTP) as a response value. The CROTP reached its maximum (25.78 %) when the fermentation pH, ultrasonic time and ultrasonic frequency were set at 5, 15 min and 50 kHz, respectively. Based on the optimization, a novel strategy was further proposed to dynamically monitor the quality change of green tea during ultrasonic-assisted fermentation (UAF) utilizing a colorimetric sensor array (CSA) comprising nine color-sensitive dyes combined with chemometric methods. The fabricated CSA showed sensitive differential responses to green tea fermentation samples, reaching the best quantitative prediction of tea polyphenol content using support vector machines (SVM) with Rc = 0.886, RMSEC = 0.042 mg/g, Rp = 0.862, and RMSEP = 0.043 mg/g. As a result, our work proved that integrating CSA with SVM is viable for dynamic quality monitoring of green tea during UAF. Furthermore, this research could be of benefit in controlling production specifications and designing ideal green tea fermentation systems.

Ultrasound-assisted fermentation of Porphyra yezoensis sauce at different growth stages using Lactiplantibacillus plantarum: Metabolic response and biological activity

This study first employed ultrasonic-assisted fermentation of seaweed foot material with Lactiplantibacillus plantarum to produce Porphyra yezoensis sauce. The aim was to examine L. plantarum's growth and metabolism of nutritional components at different growth stages under low- (133.99 W/L) and high-ultrasonic power densities (169.17 W/L). After 24-h fermentation, L. plantarum exhibited a 21.32 % increase in the sonicated P. yezoensis sauce at 133.99 W/L and the logarithmic growth phase compared to that at 169.17 W/L. In addition, compared to the non-sonicated sauce, total phenolic and flavonoid contents increased by around 58 % and 27 % in sonicated sauce at 133.99 W/L, reaching 92.38 mg GEA/g DW and 111.08 mg RE/g DW, respectively. Principal Component Analysis (PCA) of the evaluation criteria for different fermentation stages under 133.99 W/L power ultrasonication revealed that the P. yezoensis sauce generated more phenolic compounds and exhibited stronger antioxidant capabilities in the sonicated sample at the logarithmic phase of L. plantarum. Compared to the traditional treated P. yezoensis sauce, the content of free amino acids was significantly increased in sonicated sauce, especially for logarithmic phase. Finally, GC-IMS analysis demonstrated that the ultrasonication at logarithmic phase released more volatile compounds compared to the non-sonicated sauce. This led to a reduction in the fishy odour of the Porphyra yezoensis sauce and an improved release of favourable flavour compounds.

Ultrasound-assisted fermentation for antioxidant peptides preparation from okara: Optimization, stability, and functional analyses

This study investigated the effects of ultrasound-assisted fermentation (UAF) on the preparation of antioxidant peptides (UAFP) from okara and examined their content, chemical structures, and antioxidant activity. After the optimal ultrasonic processing (time, 20 min; frequency, 45 KHz; power, 120 W/L), the peptide content yield reached the maximum of 12.36 ± 0.02 mg/mL, and their DPPH free radical scavenging rate was 65.15 ± 0.32 %. UAF increased the number of globular aggregates with deeper gullies, a looser structure, and higher porosity. The experiments conducted using the oxidative stress injury model of HepG2 cells showed that okara UAFP promoted cell growth and exerted a protective effect. Moreover, ultrasonic treatment remarkably improved the environmental stability (NaCl, glucose, sodium benzoate, temperature, pH, metal ions) and antioxidant activity of UAFP. Concisely, optimal ultrasonic processing can aid the fermentation of agroindustrial by-products to prepare antioxidant peptides, such as natural food antioxidant peptides from soybean waste.

Effect of ultrasound-assisted fermentation on physicochemical properties and volatile flavor compounds of Chinese rice wine

The traditional fermentation method for Chinese rice wine (RW) production has some limitations such as difficulty in controlling quality, long brewing time, and thin taste. In this study, ultrasonic technology was adopted by adding enzyme with the aim of improving the fermentation efficiency and volatile flavor quality of RW. Results showed that the ethanol yield was increased by 23.53 % and the fermentation time was reduced by nearly 2 days by ultrasonic treatment of (one-time, 28 kHz, 1 h, 35 W/L) on the first day. Flavor analysis (following the ultrasonic treatment) showed that the flavors, especially the esters and alcohols in RW, also enhanced most significantly. The contents of isobutyl acetate, ethyl butyrate, ethyl hexanoate, and phenethyl acetate increased by 58.03 %, 107.70 %, 31.84 %, and 18.71 %, respectively. The results showed that the brewing process could be simplified, brewing time could be reduced and volatile flavor of RW could be improved by ultrasound.

Ultrasound-assisted fermentation of ginkgo kernel juice by Lactiplantibacillus plantarum: Microbial response and juice composition development

This study is aimed to explore the feasibility of ultrasound on enhancing the fermentation properties of ginkgo kernel juice by Lactiplantibacillus plantarum Y2. Specifically, ultrasound at 20 kHz and different intensities (mild ultrasound intensity-84.42 W/L, moderate ultrasound intensity-115.50 W/L, high ultrasound intensity-173.88 W/L) with a pulse mode were applied to facilitate the fermentation process. The number of viable cells of Lactiplantibacillus plantarum Y2 increased by 5.06, 5.05 and 2.19% in the sonicated groups at 173.88, 115.50 and 84.42 W/L, compared with the non-sonicated juice after 24-h fermentation. Furthermore, mild intensity ultrasonication improved the permeability of the cell membrane, which is beneficial for the metabolism of phenolics, amino acids and organic acids. Ultrasonication increased in-vitro antioxidant activity of fermented ginkgo kernel juice by promoting the metabolism of phenolic acids, such as ferulic acid, chlorogenic and caffeic acids. At the end of fermentation, the sonicated group at 84.42 W/L has the maximum consumptions of total sugars and proteins (increased by 12.52 and 18.73%). Moreover, the reduction rate of the poison material 4′-O-methylpyridoxine (MPN) in ginkgo kernel juice increased by more than 16.40% with ultrasound treatment at 173.88 W/L after the fermentation for 48 h. Overall, ultrasound can improve the metabolizations of Lactobacillus plantarum and reduce the toxic substances, which promoted the nutritional value and flavors of ginkgo kernel juice.

Impact of ultrasound-assisted fermentation on buffalo yogurt production: Effect on fermentation kinetic and on physicochemical, rheological, and structural characteristics

This work evaluated the buffalo milk acidification kinetics using partially or fully ultrasound-assisted fermentation and yogurt characteristics without or with sugar (5%). The results showed that assisted fermentation in an ultrasonic bath (25 kHz, 38 W/L) accelerates the fermentation rate (up to 41% increase), reducing the fermentation time (up to 2 h), and, in some conditions, improved the yogurt quality. Samples produced by US-assisted fermentation under 1 or 2 h had higher water holding capacity (up to 35%), consistency index (up to 423%), and apparent viscosity (up to 246%), explained by the formation of a stronger gel, as elucidated by microscopy images. In contrast, no differences in pH, acidity, and lactic acid bacteria viability were observed. Additionally, sucrose contributed positively to the yogurt quality, improving gel formation. Therefore, buffalo milk fermentation under US (up to 2 h) is an interesting strategy that accelerates fermentation and improves the buffalo yogurt quality.

Phytochemical and Structural Changes of Chickpea Beverage Prepared Using Ultrasound-Assisted Fermentation with Optimized Ultrasound Parameters Modelled by Response Surface Methodology

To improve the quality of fermented chickpea beverages, a highly nutritious substitute for dairy, the Box-Behnken design and the response surface methodology were used to obtain optimized ultrasonic parameters for producing ultrasound-assisted fermented chickpea beverages. The determining parameters were the lactic acid, reducing sugar content, and the cell viability of the treated product. The most significant parameters obtained were frequency and treatment duration, while power density was relatively insignificant. The optimum fermentation parameters obtained were a treatment start time of 3 h, treatment duration of 80 min, frequency of 27.5 kHz, and power density of 100 W/L with optimum yields of 0.23096 mg/mL, 2.92898 mg/mL, and 0.488189 for reducing sugar, lactic acid, and cell viability index, respectively, with desirability above 0.95. Further analysis of the ultrasound treatment’s effect on the product’s structure showed the ultrasound-assisted fermented chickpea beverage was more structurally stable and homogenous, with even distribution of macromolecules present.

Efficacy of Ultrasound-Assisted Lactic Acid Fermentation and Its Effect on the Nutritional and Sensory Quality of Novel Chickpea-Based Beverage

Ultrasound-assisted fermentation is a promising approach for improving food products’ nutritional and sensory qualities. This study compared the effects of ultrasound-assisted fermentation on chickpea-based beverages’ nutritive and sensory components. Proximate, phytochemical, and microstructural data were examined to evaluate the effectiveness of the processing techniques. The processed samples demonstrated significantly higher (p < 0.05) nutritional and sensory outcomes compared to the unfermented sample. The unfermented sample had a total phytochemical level of 55.41 g/mL, whereas the fermented and ultrasound-assisted fermented samples had phytochemical contents of 66.71 and 64.51 µg/mL, respectively. With values of 8.37 ± 0.11 and 7.21 ± 0.06, respectively, on a 9-point hedonic scale, the sensory evaluation revealed that the traditionally fermented sample had a greater acceptability rate than the ultrasound-treated sample. The presence of organic acids in the final product was shown to be significantly impacted by fermentation, with propanoic having the highest concentrations of 1.79 ± 3 × 10−5a, 5.56 ± 2 × 10−5b, and 3.50 ± 0.00344c mg/mL for the unfermented, fermented, and ultrasound-assisted fermented beverages, respectively. According to these results, using ultrasound-assisted fermentation with reduced fermentation time can improve chickpea-based beverages’ nutritional and functional benefits.

Ultrasound-Assisted Fermentation to Remove Cadmium from Rice and Its Application.

Rice, which is a major part of the daily diet, is becoming more and more contaminated by cadmium (Cd). This study combined low-intensity ultrasonic waves with the Lactobacillus plantarum fermentation method and optimized this technique by a single-factor and response surface experiment, aiming to solve the practical problems that the current Cd removal methods for rice cannot address, due to the fact that they require a long time (nearly 24 h), which prevents meeting the rice production demands. The described technique required a short time (10 h), and the highest Cd removal reached 67.05 ± 1.38%. Further analysis revealed that the maximum adsorption capacity of Lactobacillus plantarum for Cd increased by nearly 75%, and the equilibrium adsorption capacity increased by almost 30% after the ultrasonic intervention. Additionally, a sensory evaluation and other experiments proved that the properties of the rice noodles prepared from Cd-reduced rice obtained by ultrasound-assisted fermentation were comparable to those of traditional rice noodles, indicating that this method can be used in actual rice production.

Biomolecules in modern and sustainable agriculture.

This review presents scientific findings which indicate biomolecules are excellent candidates for the development of biopesticides. Efforts are being done to find routes to increase their concentrations in the cultivation media because this concentration facilitates applications, storage, and transportation. Some of these routes are co-fermentation and ultrasound-assisted fermentation. Ultrasonication increases metabolite production and growth rates by improvement of cell permeability and nutrient uptake rates through cell membranes. For example, 24% increase in the enzymatic activity of cellulases produced by Trichoderma reesei in solid-state fermentation was achieved with ultrasonication. Also, chitinase and β-1,3-glucanase productions were stimulated by ultrasound in Beauveria bassiana cultivation, presenting positive results. The common parameters evaluated in the production of biomolecules by ultrasound-assisted fermentation are the duty cycle, time of application, power, energetic density, and how long the sonication is maintained in the fermentation media. Many successful cases are reported and discussed, which include the final formulation of bioproducts for agricultural applications. In this trend, nanotechnology is a promising tool for the development of nanoformulations. Nanoemulsification, green synthesis, biosynthesis, or biogenic synthesis are technologies used to produce such nanoformulations, allowing the controlled release of control agents, as well as the delivery of biomolecules to specific targets.

Influence of Low-Intensity Ultrasound on ε-Polylysine Production: Intracellular ATP and Key Biosynthesis Enzymes during Streptomyces albulus Fermentation.

The effect of low-intensity sonication treatment on cell growth, ε-polylysine (ε-PL) yield and its biological mechanism were investigated, using a 3-L-jar fermenter coupled with an in situ ultrasonic slot with a Streptomyces albulus strain SAR 14-116. Under ultrasonic conditions (28 kHz, 0.37 W cm-2, 60 min), a high biomass of SAR 14-116 and concentration of ε-PL were realized (i.e., they increased by 14.92% and 28.45%, respectively) when compared with a control. Besides this, ultrasonication increased the mycelia viability and intracellular ATP as well as activities of key enzymes involved in the ε-PL biosynthesis pathway, resulting in an improvement in the production of ε-PL. Data on qRT-PCR revealed that ultrasonication also affected the gene expression of key enzymes in the ε-PL biosynthesis pathway, including ε-PL synthetase (PLS). These outcomes provided the basis for understanding the effects of ultrasound-assisted fermentation on the stimulation of metabolite production and fermentation procedure in a fermenter.

Coupling chemical degumming with enzymatic degumming of ultrasound pre-treated ramie fiber using Bacillus subtilis ABDR01

In this study, we designed, developed, and optimizedan enzymatic fiber degumming process. First, a Partially Purified Enzyme Solution (PPES) containing pectinase, cellulase and xylanase was co-produced via ultrasound-assisted fermentation of orange peels using Bacillus subtilis ABDR01. Then, degumming with PPES was optimized for pH, temperature, incubation time and PPES concentration. Finally, three sets of ultrasound-assisted degumming experiments — chemical, enzymatic, and coupled enzymatic-chemical degumming with reduced alkali concentration (0.5% NaOH, 30 min) were performed. Chemical degumming for 2 h with 1% NaOH at 98 °C resulted in residual gum content of 5.9%, whereas ultrasound-assisted (30 min, 25 kHz) chemical degumming reduced the gum content to 3.1%. At a pH of 7.5, temperature of 45 °C, 30 h incubation and 2% PPES, gum removal efficiency of >60% and fibers with <10% residual gum were produced. Coupling the ultrasound-assisted enzymatic degumming with reduced alkali chemical degumming resulted in gum content of <3%. • High frequency ultrasonicaton pre-treatment improves fiber degumming. • Combining enzymatic and chemical degumming reduced NaOH demand. • Optimized the ultrasound-assisted enzymatic degumming of Ramie fibers. • Fibers (ø 0.05 mm) containing < 3% gum and high tensile strength produced.

Comparative bioreactor studies of different process enhancement methods in B. licheniformis for enzyme co-production

Conventional fermentation processes need to be upgraded to produce a wide array of biomolecules to overcome lower product yield. The cost of production of biomolecules using the fermentation method could be reduced by increasing the product yield by various process enhancement methods. In this study, different innovative process enhancement methods were evaluated to increase the co-production of uricase and alkaline protease at the bioreactor level. Ultrasound-assisted fermentation (UAF), Extractive fermentation (ATPS), and Ultrasound-assisted extractive fermentation (UATPS) are the three innovative methods used for process enhancement. Maximum enzyme production was obtained in a combinatorial approach of ultrasound and extractive fermentation, i.e., ultrasound-assisted extractive fermentation where uricase and protease production enhanced by 2.5 fold and 1.9 fold, respectively, as compared to conventional fermentation.

Ultrasonic modification on fermentation characteristics of Bacillus varieties: Impact on protease activity, peptide content and its correlation coefficient

This study aimed to investigate the regulative effects of low-intensity ultrasound on the biomass, protease activity, and peptide content of eight Bacillus strains upon casein as substrate. Protease expression types (constitutive and inducible) were evaluated among eight Bacillus strains based on casein and its hydrolysates media. During ultrasound-assisted fermentation (UAF) of casein with Bacillus varieties, B. amyloliquefaciens 20029 displayed the highest increment in protease activity (37.33%) and peptide content (21.63%). Under the optimal ultrasonic parameters (frequency of 40 kHz, power density of 30 W/L and duration of 15 min after cultivation for 4 h), the protease activity and peptide content from casein fermented with B. amyloliquefaciens 20029 increased by 50.00% and 45.00%, respectively, compared with the control. According to Person's correlation analysis, peptide content had a highly negative correlation (r = −0.77) with protease activity based on eight Bacillus strains, and the r value became −0.75 after extra-adding B. amyloliquefaciens 20029 based on UAF. The practical fermentation of soybean meal and corn gluten meal with B. amyloliquefaciens 20029 further confirmed that ultrasound effectively improved peptide contents by its inducible protease expression. This finding provided a vital reference for screening fermentation strains and substrate proteins during UAF.

Ultrasound-assisted fermentation for enhancing metabolic and probiotic activities of LactoBacillus brevis

This study investigated the changes in metabolic and probiotic activities of .Lactobacilluse brevis (LMG 6906) throughout ultrasound-assisted fermentation. Moderate ultrasound treatments (23 kHz, 10 µm amplitude for 3main and 5 min) resulted in up to 1.09 log CFU/mL increase in Lb. brevis cell counts, 58.17 - 82.59% increase in specific growth rate, and 16 - 36.25% increase in cell membrane permeability. This was accompanied by a lower pH of 0.51, a higher titratable acidity of 0.95 mg/L, and up to 36.42% increase in protein hydrolysis with a 0.26 g/L (31.76%) increase in GABA yield. However, a higher ultrasound intensity (15 µm amplitude) was relatively lethal for Lb. brevis that led to a lower metabolic activity i.e., 0.25 - 0.30 g/L (30.58 - 36.47%) reduction in GABA yield. The Fourier transform infrared spectroscopy indicated Lb. brevis cells exposed to the sonication undergo damage or conformational/compositional alterations in DNA/RNA, cellular proteins, cell membrane, and cell wall, however, further studies are required to permit a better employment of this tool in cellular study. We speculate that low intensity ultrasound is applicable for manufacturing GABA-rich fermented products by Lb. brevis as a probiotic supplement.

Mechanistic investigations in ultrasound-induced intensification of fermentative riboflavin production

This paper reports mechanistic studies in ultrasound-assisted riboflavin production by wild strain of D. hansenii var. hansenii. Statistical optimization of fermentation resulted in riboflavin yield of 1.8 mg/g DCW. Supplementation of medium with glycine, Fe3+, cobalt and zinc further enhanced yield to 4.1 mg/g DCW. Intensification of fermentation by sonication (at 10% duty cycle) in four intervals of 12 h each (in total log phase of 48 h) was attempted. Sonication in final 12 h of log phase was most effective with the highest yield of 20 mg/g DCW. Kinetic analysis of the ultrasound-assisted fermentation revealed higher maximum specific growth rate of cells (0.30 h−1) with reduced Monod constant (5.67 g/L), indicating faster cell transport and higher substrate affinity. SDS-PAGE analysis of proteins involved in riboflavin metabolism showed overexpression of all proteins in ultrasound-assisted fermentation, which enhanced the metabolism. These results are attributed to intense microturbulence generated by sonication.

Ultrasound-assisted fermentation for cider production from Lebanese apples.

The present work studies the impact of low-intensity ultrasound (US) on Hanseniaspora sp. yeast fermentations. The effect of pulse duration and growth phase on US application was first evaluated using a synthetic medium. The optimal conditions were then applied to apple juice US-assisted fermentation. An US treatment chamber was first designed to allow the recycling of the culture medium. The optimal US pulse duration on the yeast growth rate was of 0.5s followed by 6s rest period, and during 6h of both Lag and Log phases. These US parameters led to a faster consumption of glucose in the medium during the fermentation, compared to the untreated culture. The impact of US was also depending on the growth phase, showing higher sensitivity of the yeast to US during the Lag phase rather than the Log phase. US-assisted fermentation of apple juice showed a significant increase in biomass growth and glucose consumption, along with a significant decrease in the ethanol yield. The fastest growth kinetic (by 52%), and the highest ethanol reduction (by 0.55% (v, v)) were obtained for the treatment during the first 12h of fermentation, thereby, the stationary phase was reached faster, and the maximum biomass growth rate was 10 folds higher compared to the untreated culture. The results obtained in this study demonstrated the promising efficiency of US-assisted fermentation in stimulating the biomass growth and reducing the ethanol content in alcoholic beverages.

Enhancement of rhamnolipid production through ultrasound application and response surface methodology

Abstract In the past few decades, chemically synthesized surfactants are routinely getting deposited on land and water systems, by industrial and domestic waste. Some of them are toxic to animals, ecosystem, and humans. The demand for microbial surfactants is progressively increasing due to their diverse and heterogeneous nature that can be applied to reduce surface and interfacial tension across a wide range of industrial and environmental applications. Pseudomonas stutzeri, a well-known organism for bioremediation was used for the production of rhamnolipid, along with the use of ultrasound to enhance the productivity of bio-surfactant during the fermentative production. The aim was to identify the sonication regime suitable for improving the productivity of a varied range of bioprocesses and to elucidate the enhancement using response surface methodology. Ultrasound-assisted fermentation resulted in 1.5 folds more rhamnolipid than the conventional method with 150 W ultrasound power, 6 min of irradiation time and 42.5% duty cycle. The maximum yield of rhamnolipid obtained was 4.78 g/L. Various methods for applicability of the produced bio-surfactant were also studied. This study is the first report for ultrasound assisted enhancement of biosurfactant to the best of our knowledge.

Ultrasonic enhancement of xylitol production from sugarcane bagasse using immobilized Candida tropicalis MTCC 184

This study investigates ultrasonic enhancement of xylitol production from sugarcane bagasse using C. tropicalis MTCC 184 immobilized on PU foam. Initial xylitol yield of 0.53 g/g xylose improved to 0.65 g/g of xylose (in 36 h fermentation) after optimization of medium and fermentation parameters. Optimum values of experimental parameters for maximum xylitol were: yeast extract = 5.78 g/L, (NH4)2SO4 = 3.22 g/L, KH2PO4 = 0.58 g/L, MgSO4·7H2O = 0.57 g/L and temperature = 29.3 °C, initial pH = 6.2, agitation rate = 151 rpm and initial xylose concentration = 20.9 g/L. Application of 37 kHz sonication @10% duty cycle during fermentation at optimum conditions resulted in marked intensification of fermentation kinetics. Xylitol yield of 0.66 g/g of xylose has been obtained in ultrasound-assisted fermentation in just 15 h. Fitting of time profiles of substrates and products to kinetic model has highlighted actual physical mechanisms underlying 2-fold faster kinetics induced by sonication.