Mahejibin Khan

Ferulic acid esterases (FAEs) are enzymes that interact with esterified components of plant cell walls, facilitating the release of free ferulic acid (FA) from plant materials. Therefore, they hold significant importance across multiple industries, including pharma, food, and cosmetics. This investigation involved the cloning, expression, and characterization of FAE from the human fecal metagenome. Sequence analysis revealed that the cloned gene was approximately 750 bp in length and contained an open reading frame encoding a protein of 252 amino acids. The resulting recombinant protein displayed a molecular weight of 28 kDa and 49.7% identity with the chlorogenic acid esterase from Lactobacillus helveticus . The hydrolytic activity of the recombinant FAE was validated using p ‐nitrophenyl‐ferulate (pNPF) as the substrate, with optimal activity at a pH of 7 and a temperature of 35°C. The enzyme showed stability within a pH range of 5.0–7.0 and temperatures from 5°C to 35°C. High‐performance liquid chromatography (HPLC) results indicated that the FAE enzyme could release up to 49.7% of total alkali‐extractable FA from dehydrated rice bran, followed by wheat bran and sugarcane bagasse. The total phenolic content of sugarcane bagasse increased by approximately 100% after in situ enzymatic fermentation compared with the chemically extracted fraction. These results indicate that cloned FAE can be used as a potential biocatalyst in industrial applications.

Gut microbiota plays an important role in regulating enteric, immune and neural pathways. Many neuropsychiatric disorders such as anxiety, depression, autism and cognitive behaviour are associated with gut dysbiosis. Gamma-aminobutyric acid (GABA) and short-chain fatty acids produced by gut bacteria influence gastrointestinal and neurological functions. Ferulic acid esterase (FAE) which releases ferulic acid (FA) from feruloylated sugar ester conjugates, naturally found in grains, fruits and vegetables, is also produced by some gut bacteria and helps prevent neurodegeneration. These properties provide bacteria with the ability to maintain intestinal barrier function and prevent neuropsychiatric disorders. Therefore, this study aims to isolate GABA and FAE-producing LAB and characterize their bioactive and probiotic properties. A total of twelve cultures were isolated, of which eight bacteria positive for GABA, FAE and SCFA production were selected for further investigation. All selected bacteria were positive for bile salt hydrolase (BSH) and showed acid tolerance, resistance to bile salt, stimulated gastric and pancreatic juice, and auto- and co-aggregation properties. Furthermore, selected LAB showed mucin adhesion efficiency greater than 80% and exhibited γ-hemolytic activity. 16S rRNA sequencing identified NS0969, B1, C1, C2, M1, M2, and R2 as Limosilactobacillus fermentum and R1 as Lactiplantibacillus pentosus. This study showed that selected bacteria and/or their postbiotic preparations can be used as potential psychobiotics.

Oxidative stress is an imbalance between free reactive oxygen species and antioxidant defences leading to neurological and other chronic disorders. The interaction between food and gut microbiota and their metabolites significantly reduces oxidative stress and influences host physiology and metabolism. This process mainly involves enzymes that hydrolyse complex polysaccharides and produce metabolites. Ferulic acid esterases (FAE) one of the most important enzymes of the gut microbiome, release ferulic acid from feruloylated sugar ester conjugates, that occur naturally in grains, fruits, and vegetables. FA is crucial in combating oxidative stress resulted from free radical formation. This study investigated the effect of two plant-based nutraceutical formulations, cereal-millet-based (PC1) and fruit-vegetable-based (PC2), on gut microbiota and the production of FAE, short chain fatty acids (SCFA) and other small metabolites in in vitro fermentation using human faecal samples. After in vitro fermentation, both nutraceutical formulations increased the abundance of Bifidobacterium, Lactobacillus, Prevotella, Feacalibacteria, and Clostridium leptum. Furthermore, they induced the production of FAE, xylanase and pectinase enzymes, SCFA and other small metabolites, resulting in increased antioxidation activity of the fermentate. PC1 stimulated FAE and xylanase production more effectively. These results demonstrated a positive correlation between the feruloylated nutraceutical formulation and the production of FAE and other accessory enzymes, suggesting that PC1 and PC2 stimulate the proliferation of the FAE-producing microbial consortium of the gut microbiome and therefore, increase FA and SCFA concentration. From this study it is evident that FA-rich plant-based formulation can be used as a prophylactic nutraceutical supplement to alleviate oxidative stress by modulating the gut microbiota. Graphical Abstract

Purpose of the review Ferulic acid (FA), which occurs naturally as the feruloylated sugar ester in grains, fruits, and vegetables, is critical for combating oxidative stress and alleviating neurodegenerative diseases resulting from free radical-generated protein aggregates in brain cells. However, FA cannot be absorbed in conjugated form. Therefore, strategies to improve the bioavailability of FA are gaining more importance. Ferulic acid esterases (FAE) of the gut microbiota are critical enzymes that facilitate FA release from feruloylated sugar ester conjugates and influence systemic health. This review provides insight into a nutrition-based approach to preventing neurodegenerative disorders such as Alzheimer’s and Parkinson’s by altering the diversity of FAE-producing gut microbiota. Recent findings The human gut is a niche for a highly dense microbial population. Nutrient components and the quality of food shape the gut microbiota. Microbiota–diet–host interaction primarily involves an array of enzymes that hydrolyse complex polysaccharides and release covalently attached moieties, thereby increasing their bio-accessibility. Moreover, genes encoding polysaccharide degrading enzymes are substrate inducible, giving selective microorganisms a competitive advantage in scavenging nutrients. Summary Nutraceutical therapy using specific food components holds promise as a prophylactic agent and as an adjunctive treatment strategy in neurotherapeutics, as it results in upregulation of polysaccharide utilisation loci containing fae genes in the gut microbiota, thereby increasing the release of FA and other antioxidant molecules and combat neurodegenerative processes.

Background: The disease severity, ranging from being asymptomatic to having acute illness, and associated inflammatory responses has suggested that alterations in the gut microbiota may play a crucial role in the development of chronic disorders due to COVID-19 infection. This study describes gut microbiota dysbiosis in COVID-19 patients and its implications relating to the disease. Design: A cross sectional prospective study was performed on thirty RT-PCR-confirmed COVID-19 patients admitted to the All India Institute of Medical Sciences, Bhopal, India, between September 10 and 20, 2020. Ten healthy volunteers were recruited as the control group. IFN, TNF, and IL-21 profiling was conducted using plasma samples, and gut bacterial analysis was performed after obtaining the metagenomics data of stool samples. Results: Patients with a variable COVID-19 severity showed distinct gut microflora and peripheral interleukin-21 levels. A low Firmicute/Bacteroidetes ratio, caused by the depletion of the fibre-utilizing bacteria, F. prausnitzii, B. Plebius, and Prevotella, and an increase in Bacteroidetes has associated gut microbiota dysbiosis with COVID-19 disease severity. Conclusions: The loss of the functional attributes of signature commensals in the gut, due to dysbiosis, is a predisposing factor of COVID-19 pathophysiology.

Pectin is a branched heteropolysaccharide consisting of long-chain galacturonan segments and other neutral sugars such as rhamnose, arabinose, galactose, and xylose. It forms a matrix with celluloses and hemicelluloses and contributes to the cell structure. Due to the presence of several sugar moieties and different levels of methyl esterification, pectin does not have defined molecular weight like other polysaccharides. Pectin has wide applications. It is used as emulsifier, gelling agent, thickener, stabilizer, and fat or sugar replacer in low-calorie foods. Pectin and pectin-derived oligosaccharides can also be used as an important ingredient in functional foods. In recent past, a new application envisaged for pectin polymers as edible films or coating. These films act as natural barrier for exchange of moisture, gases, lipids, and volatiles between food and environment, and protect fruits and vegetable from microbial contamination. The degree of esterification of pectin and other structural modifications defines the functional properties. Herein, various functional properties of pectin in relation to food processing and packaging are discussed.