Blueberry wines provide a nutrient-rich alternative to perishable fresh fruits. However, the flavor complexity and nutrition retention remain limited by traditional fermentation. In this study, a non-Saccharomyces yeast Clavispora sp. LM32 was introduced into the Saccharomyces cerevisiae based blueberry fermentation. Ethanol levels were all reduced in simultaneous and sequential fermentation groups. Anthocyanin contents in simultaneous fermentation, sequential fermentation inoculating strain LM32 after 24 h (SEQ24), sequential fermentation inoculating strain LM32 after 48 h (SEQ48), were increased by 17.52, 38.59, and 43.87%, respectively. Meanwhile, SEQ24 brought significantly altered contents of volatile compounds, with higher alcohols increased by 19.85%, increased ethyl esters by 348.29%, acetate esters decreased by 18.43%, and synthesis of norisoprenoids and terpenes enhanced. Specially, contents of hexadecanoic acid ethyl ester and octanoic acid methyl ester in SEQ24 were increased by 4.6 times and 3.3 times, respectively, which can impart distinct tropical fruit and creamy fullness notes to the blueberry beverage. Sensory analysis demonstrated that sequential fermentation enhanced both fruity and sweet attributes. The study highlights the role of Clavispora sp. for enhancing aromatic profiles flavor and nutritional retention, proposing sequential fermentation as an optimal strategy for premium blueberry beverages.

Introduction:Erythromycin poses significant ecological risks to marine ecosystem due to its persistence and lipophilic properties. However, the response mechanism of marine microalgae to erythromycin remains inadequately understood. Methods:Phaeodactylum tricornutum was exposed to 0-40 mg/L erythromycin; growth, photosynthetic pigments, and oxidative stress markers were measured. Nile red staining, lipidomics, and transcriptomics were used to analyze lipid remodeling and metabolic pathway changes. Results:High-dose erythromycin exposure concentration-dependently inhibited algal growth, disrupted photosynthetic pigments, and induced oxidative stress. Notably, erythromycin triggered a pronounced lipid redistribution, characterized by altered glycerolipid and glycerophospholipid profiles, increased lipid accumulation, and enhanced unsaturated fatty acid profile. Transcriptomic analyses confirmed that ERY-induced lipidome remodeling affected critical pathways to provide precursors and reducing power degradation for fatty acid synthesis, and the pathway of fatty acid degradation. Conclusion:These findings elucidate the intrinsic mechanistic link between antibiotic-induced lipid dysregulation and the physiological resilience of diatoms, providing novel insights into the molecular toxicology of antibiotics in primary producers.

Alginate lyases are commonly employed for producing alginate oligosaccharides (AOS), but their industrial application is often constrained by low thermal stability and catalytic efficiency. This study engineered mutants of alginate lyase Alyw203 from marine Vibrio based on B-factor values and negative ΔΔG values. The L172V mutant exhibited a 2.43-fold increase in half-life at 40 °C, reduced Km (from 107 to 65 mg/mL), and enhanced kcat/Km (from 0.07 to 0.35 mL/mg/s), indicating improved thermal stability, substrate affinity, and catalytic efficiency. Molecular dynamics simulations revealed that these improvements originated from reconstructed hydrogen bond networks, which stabilized enzyme–substrate interactions and reduced conformational flexibility. These results demonstrate that rational design focused on strengthening hydrogen bonding can simultaneously improve both stability and activity, offering a promising strategy for industrial AOS production.

Aurantiochytrium limacinum is recognized as an ideal candidate to produce docosahexaenoic acid (DHA). However, elevating the biomass and lipid yield on a large scale is still a challenge. In this study, a simple and feasible strategy for enhancing DHA accumulation based on Laminaria japonica hydrolysate (LPH) addition has been developed. The addition of 40 mL/L LPH enhanced the accumulation of biomass and lipid of A. limacinum by 31.48% and 49.48%, respectively. Meanwhile, the DHA production was increased by 40.78%. By investigating the effects on DHA and biomass accumulation hormones in LPH, gibberellin 3, abscisic acid, and salicylic acid were characterized as the key factor. With the addition of LPH, the upregulated genes were enriched in pathways including fatty acid biosynthesis, metabolism, and the tricarboxylic acid cycle. In particular, key genes involved in fatty acid synthesis, such as ACC1 and FAS2, were significantly upregulated. In this study, LPH was identified as a novel additive with practical application value due to its readily available and low-cost raw ingredients.

Antibiotic cocktails (ABX) serve as potent therapeutic interventions for refractory ulcerative colitis (UC), yet invariably induce gut dysbiosis. This study demonstrates that pectin oligosaccharides synergistically enhance ABX efficacy by restoring gut microbiota balance and selectively enriched antibiotic-resistant Parabacteroides goldsteinii in a colitis mouse model. Our results further indicate that the gavage administration of P. goldsteinii AM58-2XD markedly alleviated colitis via enhancing the branched-chain amino acid metabolic pathway, particularly by facilitating valine metabolism. Notably, these anticolitis effects were partially attenuated in P. goldsteiniiΔilvE mutants, which are defective in valine-derived isobutyrate (IBN) biosynthesis. We further demonstrated that exogenous IBN supplementation effectively alleviated colitis symptoms in mice and enhanced gut barrier function via activation of the peroxisome proliferator-activated receptor γ (PPARγ) pathway. Conditional knockout of PPARγ in Caco-2 intestinal epithelial cells markedly abrogated the IBN-induced enhancement of tight junctions, thereby substantiating the critical role of the IBN-PPARγ pathway in metabolite-mediated mucosal repair. Collectively, we delineate a prebiotic/probiotic–metabolite axis wherein P. goldsteinii facilitates mucosal repair via IBN/PPARγ-dependent epithelial metabolic reprogramming. This insight redefines antibiotic-resistant commensals as precise biotherapeutics for microbiota restoration in refractory UC management.

Phaeodactylum tricornutum have garnered significant attention for its ability to accumulate fucoxanthin (Fx) and eicosapentaenoic acid. However, its limited biomass in autotrophic culture becomes a restrictive factor for the large-scale production of Fx. Herein, 6-benzylaminopurine and 5-aminolevulinic acid at 1.0 mg/L, were proved conducive for promoting the Fx and biomass accumulation. Under the combined effect of the two, Fx and peaked at 36.01 mg/L after 10 d of cultivation, at which point biomass was 1.50 g/L and Fx content was 24.01 mg/g. Meanwhile, EPA production was elevated to 22.73 mg/L. Such combined effect was also found in regulating the transcriptional levels of Fx biosynthesis-related genes by the two plant hormones. This study demonstrates that Fx and biomass can be enhanced easily and efficiently under the combined effect of these two plant hormones, enabling massive Fx production in the autotrophic system.

Pelagic Sargassum is invasive macroalgae with huge biomass. To produce bulk chemicals with profit from the biomass, innovative strategies need to be developed. In this study, maximum saccharification yield of Sargassum horneri biomass was obtained with the combined use of 3% alginate lyase and 3% cellulase, releasing 20.83 g/L glucose and 1.73 g/L mannitol at a 1:6 feed ratio. Subsequently, the crude S. horneri hydrolysate (pH 3.0) was proved most suitable for erythritol production of Yarrowia lipolytica strain. After 60 h fermentation in a 10-L fermenter, the erythritol concentration reached 18.42 g/L with a yield of 0.82 g/g; while the concentration of alginate oligosaccharides (AOS) was 37.56 g/L. Finally, AOS with a purity of 93.4% were obtained by ethanol precipitation, and erythritol was harvested via crystallization. This proposed strategy demonstrates the feasibility of transforming invasive Sargassum into two high-value chemicals for the first time.

Enzymatic alginate oligosaccharides were proved with various biological activities. Developing robust alginate lyase with high production is essential for its industrial application. In this study, a novel alginate lyase gene, AL07, was successfully screened and expressed in Pichia pastoris, and its characteristics were characterized. The secreted alginate lyase has a molecular weight of approximately 40.0 kDa and an activity of 45.4 U/mL. AL07 exhibits superior biological activity at pH 7.0 and 40 °C, with a preference for polyG substrates. Notably, the enzyme exhibits more than 60% relative activity over a pH range of 5.0 to 10.0. AL07 is also independent of ions and exhibits salt tolerance properties. The main degradation product of AL07 is DP2 oligosaccharide. Using AL07-based enzyme cocktail, Laminaria japonica can be degraded within 120 min. Therefore, AL07 has been demonstrated to be an efficient tool for the preparation of alginate oligosaccharides and the degradation of L. japonica.

The most widely used colorimetric method based on the phenol-sulfuric acid system generally has problems of poor reproducibilities and large measurement errors. In this study, bioactive Tremella fuciformis polysaccharides (TFPS) were used as the test materials, a systematic investigation was performed to solve these problems. Influences of temperature, TFPS hydrolysis, enzyme interferences, and other factors affecting the TFPS determination were intensively studied and optimized. The accurate quantification of TFPS in the presence of enzyme interference was also innovatively realized by the establishment of corrected calibration standard curves. In addition, long-term storage conditions of TFPS samples at different temperatures and storage time were also addressed and compared. This study, for the first time, completely solved the problems that existed in traditional phenol-sulfuric acid methods and thereby provided a certain theoretical basis not only for accurate detection and quantification of TFPS but for standardization and further utilization of other types of polysaccharides as well.

EDITORIAL article Front. Bioeng. Biotechnol., 21 October 2022Sec. Bioprocess Engineering Volume 10 - 2022 | https://doi.org/10.3389/fbioe.2022.990004

Fucoxanthin (Fx) has gained a growing attention due to the remarkable biological activities. The limited biomass of was the restrictive factor for Fx production in Phaeodactylum tricornutum. In this study, Laminaria japonica hydrolysate (LPH) with a low addition proportion of 1.5 ml/L, was proved to promote fucoxanthin accumulation and cell growth simultaneously. Fx topped at 27.9 mg/L after 10-d cultivation in the LPH group, with a biomass of 1.59 g/L and a Fx content of 17.55 mg/g. Three key plant hormones in LPH were screened responsible for promoting fucoxanthin accumulation. Transcriptomic analysis and qRT-PCR results showed that genes related to Fx formation were generally up- regulated. The study demonstrated that LPH addition was a feasible and efficient strategy to enhance production of fucoxanthin, facilitating the scale-up production of Fx in autotrophic culture.

In seaweed (Laminaria japonica) extraction processing, biological enzymolysis processing has been an ideal alternative to traditional chemical extraction method. In order to evaluate the extraction effects of three different processing methods, we treated the seaweed by chemical processing (CP), enzymolysis processing (EP) as well as combined enzymolysis and microbial fermentation processing (CEMP). Besides, we compared the contents of plant hormones and algiante oligosaccharides in addition to the molecular mass distribution in three kinds of seaweed extracts. We determined the alginate content, molecular mass of alginate oligosaccharide and plant hormones contents by m-hydroxydiphenyl method, HPLC and HPLC-MS, respectively. The results show that the CP method had the lowest extraction rate of alginate oligosaccharides (41.99%) with molecular mass of 200−400 D, while the EP method and CEMP method had relatively higher extraction rate of alginate oligosaccharides (90.75% and 82.21%) with molecular mass of 200−1 600 D. Indoleacetic acid (IAA) was the most abundant plant hormone among all the three extracts, ranging from 2.64 to 64.59 ng·g−1, followed by jasmonic acid (JA, 0.05−13.09 ng·g−1). The plant hormone content of the extract by CEMP method was higher than that of the other two extracts. Based on the comprehensive comparison of extraction rate of plant hormones and alginate oligosaccharides, the CEMP method is more suitable for the preparation of agricultural seaweed extract than the CP method and EP methods.

Food-grade isomaltulose exhibits significant modulation of gut microbiota and its metabolites in healthy populations. This study further explored the preventive therapeutic effect and anti-colitis potential of isomaltulose on dextran sulfate sodium-induced colitis in mice. Our results suggested that isomaltulose played a significant role in preventing colon shortening, reducing intestinal epithelial destruction and inhibiting inflammatory cell infiltration. Meanwhile, the isomaltulose supplement greatly reduced the production of pro-inflammatory cytokines and restored the balance between T helper type 17 (Th17) cells and regulatory T (Treg) cells. Pathway enrichment analysis for differentially expressed genes (DEGs) also indicated that the anti-inflammatory effect of isomaltulose was closely related to intestinal immunity. Moreover, the disturbed gut microbiota in ulcerative colitis (UC) was partially restored after treatment with isomaltulose. These results suggest that isomaltulose is a promising therapeutic agent for the prevention and adjunctive treatment of UC by maintaining intestinal immune homeostasis and remodeling the gut microbiota.

Fucoxanthin (Fx) has attracted great interest due to its remarkable biological activities such as antioxidant and anti-obesity, and its increasing demands in biopharmaceutical and cosmetic fields. However, its commercial production is limited by low yield and high cost. In this study, we isolated and identified a species of golden algae (Ochromonas sp.) capable of engulfing Microcystis aeruginosa (M. aeruginosa) and accumulating Fx. After 72 h mixotrophic cultivation of Ochromonas sp. and M. aeruginosa, the algal culture changed from green to yellow-brown, and the content of Fx and the daily production rate were up to 11.58 mg g-1, and 1.315 mg L-1 d-1, respectively. The utilization rate of M. aeruginosa was 527.27 fg cell-1. This study will not only provide a new thought to produce Fx in an efficient, low-cost, and sustainable way but an innovative method for the control and treatment of harmful cyanobacterial blooms from eutrophic freshwaters as well.

Oleaginous fungi (including fungus-like protists) are attractive in lipid production due to their short growth cycle, large biomass and high yield of lipids. Some typical oleaginous fungi including Galactomyces geotrichum, Thraustochytrids, Mortierella isabellina, and Mucor circinelloides, have been well studied for the ability to accumulate fatty acids with commercial application. Here, we review recent progress toward fermentation, extraction, of fungal fatty acids. To reduce cost of the fatty acids, fatty acid productions from raw materials were also summarized. Then, the synthesis mechanism of fatty acids was introduced. We also review recent studies of the metabolic engineering strategies have been developed as efficient tools in oleaginous fungi to overcome the biochemical limit and to improve production efficiency of the special fatty acids. It also can be predictable that metabolic engineering can further enhance biosynthesis of fatty acids and change the storage mode of fatty acids.

BACKGROUND:Curcumin exerts a suppressive effect in tumor growth by acting as a modulator of multiple molecular targets. Circular RNA hsa_circ_0007580 (circ-PRKCA) accelerates the tumorigenesis of non-small cell lung cancer (NSCLC). However, whether curcumin can regulate circ-PRKCA to inhibit NSCLC progression is unclear.METHODS:Cell viability, colony formation, apoptosis, migration, and invasion were analyzed using Cell Counting Kit-8 (CCK-8), plate clone, flow cytometry, or transwell assay. Expression of circ-PRKCA, microRNA (miR)-384, and ITGB1 mRNA (integrin subunit beta 1) mRNA were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Curcumin repressed NSCLC growth through regulating circ-PRKCA expression was validated by xenograft assay. The targeting relationship between circ-PRKCA or ITGB1 and miR-384 was verified by dual-luciferase reporter assay. The level of ITGB1 protein was measured by western blotting.RESULTS:Circ-PRKCA and ITGB1 expression were elevated in NSCLC tissues and cells, but miR-384 had an opposing tendency. After curcumin treatment, the expression tendency of circ-PRKCA, miR-384, and ITGB1 in NSCLC cells was overturned. Furthermore, curcumin impeded viability, colony formation, migration, invasion, and accelerated apoptosis of NSCLC cells, but these impacts were partially reversed by circ-PRKCA elevation, miR-384 downregulation, or ITGB1 overexpression. Also, the inhibitory effect of curcumin on xenograft tumor was further enhanced after circ-PRKCA knockdown. Notably, circ-PRKCA regulated ITGB1 expression through sponging miR-384 in curcumin-treated NSCLC cells.CONCLUSIONS:Curcumin inhibited NSCLC growth through downregulating circ-PRKCA, which regulated ITGB1 expression by adsorbing miR-384. This study provided a new mechanism to understand how curcumin inhibited the progression of NSCLC.

kappa-Carrageenase cleaves the beta-(1-4) linkages of kappa-carrageenan into kappa-carrageenan oligosaccharides (kappa-COS), which exhibit various biological activities. In this study, a glycoside hydrolase (GH) family 16 kappa-carrageenase gene, cgkA, was cloned from the marine bacterium Vibrio sp. SY01 and secretory expressed in a food-grade host, Yarrowia lipolytica. The specific activity of the purified CgkA was 12.5 U/mg. Determination of biochemical properties showed that CgkA was a thermo-tolerant enzyme, and 59.9% of the initial enzyme activity was recovered by immediately placing the sample at 20 degrees C for 30 min after enzymatic inactivation by boiling for 5 min. The recombinant CgkA was an endo-type enzyme, the main enzymatic product was kappa-carradiaose (accounting for 87.6% of total products), and kappa-carratetraose was the minimum substrate. Additionally, in vitro and in vivo analyses indicated that enzymatic kappa-carradiaose possesses anti-oxidant activity. These features make CgkA as a promising candidate for biotechnological applications in the production of anti-oxidant kappa-COS.

(1) Background: Chitooligosaccharides (COS) have numerous applications due to their excellent properties. Chitosan hydrolysis using chitosanases has been proposed as an advisable method for COS preparation. Although many chitosanases from various sources have been identified, the cold-adapted ones with high stability are still rather rare but required. (2) Methods: A novel chitosanase named CsnY from marine bacterium Renibacterium sp. Y82 was expressed in Escherichia coli, following sequence analysis. Then, the characterizations of recombinant CsnY purified through Ni–NTA affinity chromatography were conducted, including effects of pH and temperature, effects of metal ions and chemicals, and final product analysis. (3) Results: The GH46 family chitosanase CsnY possessed promising thermostability at broad temperature range (0–50 °C), and with optimal activity at 40 °C and pH 6.0, especially showing relatively high activity (over 80% of its maximum activity) at low temperatures (20–30 °C), which demonstrated the cold-adapted property. Common metal ions or chemicals had no obvious effect on CsnY except Mn2+ and Co2+. Finally, CsnY was determined to be an endo-type chitosanase generating chitodisaccharides and -trisaccharides as main products, whose total concentration reached 56.74 mM within 2 h against 2% (w/v) initial chitosan substrate. (4) Conclusions: The results suggest the cold-adapted CsnY with favorable stability has desirable potential for the industrial production of COS.

Abstract Background Raw materials composed of easily assimilated monosaccharides have been employed as carbon source for production of microbial lipids. Nevertheless, agro-industrial wastes rich in galactose-based carbohydrates have not been introduced as feedstocks for oleaginous yeasts. Results In this study, Aureobasidium namibiae A12 was found to efficiently accumulate lipid from soy molasses and whey powder containing galactose-based carbohydrates, with lipid productions of 5.30 g/L and 5.23 g/L, respectively. Over 80% of the fatty acids was C16:0, C18:0, C18:1, and C18:2. All kinds of single sugar components in the two byproducts were readily converted into lipids, with yields ranging between 0.116 g/g and 0.138 g/g. Three α-galactosidases and five β-galactosidases in the strain were cloned and analyzed. Changes of transcriptional levels indicated GalB and GalC were key α-galactosidases, and GalG was key β-galactosidase. In 10 L fermentor, lipid production from SM and WP achieved 6.45 g/L and 6.13 g/L, respectively. β-galactosidase was responsible for lactose hydrolysis; sucrase and α-galactosidase both contributed to the efficient hydrolysis of raffinose and stachyose in a cooperation manner. Conclusions This is a new way to produce lipids from raw materials containing galactose-based carbohydrates. This finding revealed the significance of sucrase in the direct hydrolysis of galactose-based carbohydrates in raw materials for the first time and facilitated the understanding of the efficient utilization of galactose-based carbohydrates to manufacture lipid or other chemicals in bioprocess. Graphic abstract