Metatranscriptomic approach reveals the functional and enzyme dynamics of core microbes during noni fruit fermentation

Multiple metabolite profiles uncover remarkable bioactive compounds and metabolic characteristics of noni fruit (Morinda citrifolia L.) at various stages of ripeness

This study aimed to investigate the changes in physicochemical properties, bioactive compounds, and metabolic characteristics of noni fruit at different ripeness levels. The results showed that there were significant differences in physicochemical properties. HPLC analysis was conducted, revealing succinic acid, scopoletin, deacetylasperulosidic acid, and asperulosidic acid were key bioactive compounds as the fruit ripened. Additionally, 4 differentbiomarkers (isocitric acid, 4,4-thiodiphenol, lobaric acid, and octocrylene), identified using 1HNMR and LC-IT-TOF-MS, were found to have a VIP value over 1. The results from HS-GC-IMS demonstrated noteworthy that 14 volatile compounds were identified as highly discriminative features during fruit ripening. Furthermore, correlation analysis showed that different ripeness had significant effects on bioactive components and functional activities, e.g., the inhibition rate of enzyme and E. coli of noni fruit with different ripeness exceeded 90% at the last stage. This study contributes new insights into the effective utilization of bioactive ingredients in noni fruit.

Investigation of volatile compounds during fermentation of Elaeagnus moorcroftii Wall.ex schlecht. juice by Bifidobacterium animalis subsp. lactis HN-3 and Lacticaseibacillus paracasei YL-29

The influence on and biotransformation of volatile compounds (VOCs) during fermentation of Elaeagnus moorcroftii Wall.ex Schlecht. juice (EWSJ) through single inoculation and co-inoculation of Bifidobacterium animalis subsp. lactis HN-3 (B.an3) and Lacticaseibacillus paracasei YL-29 (L.cp29) were analyzed through headspace-solid phase microextraction-gas chromatography-mass spectrometry. Compared with the B.an3- and L.cp29-fermented EWSJ, the B.an3 + L.cp29-fermented EWSJ had more increased 9 desirable flavor compositions and less decreased in or even elimination of 12 undesirable flavor compositions, and 3 new characteristic VOCs, formed through the interaction between B.an3 and L.cp29 were detected. In addition, biotransformations that led to an increase and a decrease in VOCs mainly involved 3 oxidation, 3 reduction, 1 hydrolysis, and 1 isomerization reactions. This study offers a theoretical basis for investigating the interaction effect of Lactobacillus and Bifidobacterium species on VOCs and developing lactic acid bacteria-fermented plant-based juices with lower sugar content and better flavor.

Analysis of endoglucanases production using metatranscriptomics and proteomics approach

The cellulases are among the most used enzyme in industries for various purposes. They add up to the green economy perspective and cost-effective production of enterprises. Biorefineries, paper industries, and textile industries are foremost in their usage. The production of endoglucanases from microorganisms is a valuable resource and can be exploited with the help of biotechnology. The present review provides some insight into the uses of endoglucanases in different industries and the potent fungal source of these enzymes. The advances in the enzyme technology has helped towards understanding some pathways to increase the production of industrial enzymes from microorganisms. The proteomics analysis and systems biology tools also help to identify these pathways for the enhanced production of such enzymes. This review deciphers the use of proteomics tools to analyze the potent microorganisms and identify suitable culture conditions to increase the output of endoglucanases. The review also includes the role of quantitative proteomics which is a powerful technique to get results faster and more timely. The role of metatranscriptomic approaches are also described which are helpful in the enzyme engineering for their efficient use under industrial conditions. Conclusively, this review helps to understand the challenges faced in the industrial use of endoglucanases and their further improvement.

Valorization of food waste fermentation liquid into single cell protein by photosynthetic bacteria via stimulating carbon metabolic pathway and environmental behaviour

Single cell protein (SCP) production by photosynthetic bacteria (PSB) is dependent on the bioavailability of carbon source, while sufficient volatile fatty acids (VFAs) in food waste fermentation liquid might be a potential alternative. It is unclear how the fermentation liquid affects the SCP biosynthesis and the related metabolic mechanism. This work demonstrated that the SCP production could be improved effectively (2088.4 mg/L) with high conversion capacity of carbon source (0.99 mg-biomass/mg-COD) by regulating carbon source level. PSB preferred to utilize the VFAs in food waste fermentation liquid. The carbon metabolic pathways (e.g., the transformation of VFAs to acetyl-CoA, and tricarboxylic acid cycle) involved in the SCP production were enhanced under optimal condition. Moreover, optimal carbon source regulation could significantly stimulate the environmental behaviour of PSB (e.g., two-component system, quorum sensing, and ATP-binding cassette transporter) involved in adaptation to external stimulus and maintaining high bacterial activity, resulting in SCP yield promotion.

Combining Transcriptomics and Polyphenol Profiling to Provide Insights into Phenolics Transformation of the Fermented Chinese Jujube

As an important medicine homologous food, Chinese jujube is rich in nutrition and medicinal value. To enhance the bioactive compounds level of Chinese jujube products, three kinds of fungi strains (Rhizopus oryzae, Aspergillus niger and Monascus purpureus) were firstly selected to evaluate their effects on total soluble phenolic compounds (TSPC) and total soluble flavonoids compounds (TSFC) contents during liquid state fermentation of Chinese jujube. As the best strain, the highest contents of TSPC and TSFC could increase by 102.1% (26.02 mg GAE/g DW) and 722.8% (18.76 mg RE/g DW) under M. purpureus fermentation when compared to the unfermented sample, respectively. Qualitative and quantitative analysis of individual polyphenol compounds indicated that proto-catechuic acid, p-hydroxybenzoic acid and chlorogenic acid showed the highest level in the fer-mented Chinese jujube at the 7th day, which was enhanced by 16.72-, 14.05- and 6.03-fold when compared to the control, respectively. Combining with RNA sequencing, function annotation of CAZymes database and polyphenol profiling, three potential transformation pathways of poly-phenol compounds were proposed in the fermented Chinese jujube by M. purpureus, such as the conversion of insoluble bound phenolic acids, rutin and anthocyanin degradation. These findings would be beneficial for better understanding of the biotransformation mechanism of polyphenol compounds in fungi fermentation.

Antimicrobial and anticancer activities of Hainan dry noni fruit alcoholic extracts and their novel compounds identification using UPLC-Q-Exactive Obitrap-MS/MS

Morinda citrifolia Linn (noni) is an important plant in the Pacific Asian region. The fruit has been used as a food source and has shown therapeutical benefits for health. Recently, it has become a source for bioactive compounds. In this study, we investigated the antimicrobial and anticancer activities of alcoholic extracts of Hainan dry noni fruit with machinery assistance and identified their novel compounds by UPLC-Q-Exactive Obitrap-MS/MS. By IE extractor aided method, the extraction of both NFE (Noni Fruit Ethanol) and NFM (Noni Fruit Methanol) solvent crude sample extracts were obtained with recovery yields of 98.48% and 71.65%, respectively. The antimicrobial effect of the crude extracts was subjected to disc diffusion test screening against two microbial strains bacterium SA (Staphylococcus aureus) and, fungal CA (Candida albicans). The MIC values of SA and CA were 35.34 and 47.80 mg/mL for NFE, 117.40 and 108.01 mg/mL for NFM, respectively. Further on, cell viability assay showed that IC₅₀ values of extract NFE and NFM on human UMUC-3 bladder carcinogenic cells were 865.1 and 789.1 µg/mL with less effect to human SVHUC-1 normal cell line for 72hr incubation. Using UPLC-Q-exactive Orbitrap-MS/MS, ten compounds were identified in the noni extracts and confirmed from the HMDB and FooDB. Five known bioactive compounds had been used for treatments in anti-cancer, anti-obesity, and Covid-19 patients. The remaining five compounds were found novel in noni fruit. They were Cyanidin 3-(2 G-xylosylrutinoside), Inulobiose, Clausarinol, Pectachol, and 4,7-Megastigmadien-9-ol. The potential bioactivities of these novel compounds will be studied in the near future. These findings form a basis on screening natural medicinal plant extracts for beneficial use as a food and health source.

Development and Validation of an Analytical Method for Deacetylasperulosidic Acid, Asperulosidic Acid, Scopolin, Asperuloside and Scopoletin in Fermented Morinda citrifolia L. (Noni)

Fermentation is a technology that enhances biologically active ingredients, improves the absorption rate and induces the generation of new functional ingredients by the catalytic action of enzyme systems possessed by microorganisms. In this study, changes in the content of five kinds of bioactive compounds (deacetylasperulosidic acid, asperulosidic acid, scopolin, asperuloside and scopoletin) of Morinda citrifolia L. were confirmed by fermentation, and a high-performance liquid chromatography-photodiode array (HPLC-PDA) analysis method for measuring analytes was developed and validated. HPLC method for the determination of five bioactive compounds in Morinda citrifolia L. extracts (MCE) was validated in terms of sensitivity, linearity, selectivity, limit of detection (LOD) and quantification (LOQ), precision and accuracy. The coefficient of determination of the calibration curve for bioactive compounds (1.56–100 μg/mL) showed linearity (R2 ≥ 0.9999). LOD and LOQ were in the range 0.04–0.97 and 0.13–2.95 μg/mL, respectively. The range of intra- and intraday accuracies values (recovery) were 97.5–121.9% and 98.8–118.1%, respectively, and precision value (RSDs) of the bioactive compounds were <4%. In addition, changes in the content of five bioactive compounds in MCE by fermentation were confirmed. These results indicate that the developed fermentation and analysis method could be applied in the development of potential functional food ingredients.

Changes in Phenols, Polysaccharides and Volatile Profiles of Noni (Morinda citrifolia L.) Juice during Fermentation

The change in phenols, polysaccharides and volatile profiles of noni juice from laboratory- and factory-scale fermentation was analyzed during a 63-day fermentation process. The phenol and polysaccharide contents and aroma characteristics clearly changed according to fermentation scale and time conditions. The flavonoid content in noni juice gradually increased with fermentation. Seventy-three volatile compounds were identified by solid-phase microextraction coupled with gas chromatography–mass spectrometry (SPME-GC-MS). Methyl hexanoate, 3-methyl-3-buten-1-ol, octanoic acid, hexanoic acid and 2-heptanone were found to be the main aroma components of fresh and fermented noni juice. A decrease in octanoic acid and hexanoic acid contents resulted in the less pungent aroma in noni juice from factory-scale fermentation. The results of principal component analysis of the electronic nose suggested that the difference in nitrogen oxide, alkanes, alcohols, and aromatic and sulfur compounds, contributed to the discrimination of noni juice from different fermentation times and scales.