The gut–brain axis (GBA) is a complex bidirectional communication network connecting the gut and brain. It involves neural, immune, and endocrine communication pathways between the gastrointestinal (GI) tract and the central nervous system (CNS). Perturbations of the GBA have been reported in many neurodegenerative disorders (NDDs), such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS), among others, suggesting a possible role in disease pathogenesis. The gut microbiota is a pivotal component of the GBA, and alterations in its composition, known as gut dysbiosis, have been associated with GBA dysfunction and neurodegeneration. The gut microbiota might influence the homeostasis of the CNS by modulating the immune system and, more directly, regulating the production of molecules and metabolites that influence the nervous and endocrine systems, making it a potential therapeutic target. Preclinical trials manipulating microbial composition through dietary intervention, probiotic and prebiotic supplementation, and fecal microbial transplantation (FMT) have provided promising outcomes. However, its clear mechanism is not well understood, and the results are not always consistent. Here, we provide an overview of the major components and communication pathways of the GBA, as well as therapeutic approaches targeting the GBA to ameliorate NDDs.

Membrane lipids form the structural basis of all cells. In the marine environment, it is well established that phosphorus availability significantly affects lipid composition in cosmopolitan marine bacteria, whereby non-phosphorus-containing lipids are used to replace phospholipids in response to phosphorus stress. Central to this lipid remodeling pathway is a newly identified phospholipase C-type metallophosphoesterase (PlcP). However, little is known about how PlcP activity is regulated. Here, we determined the role of metal ions in regulating PlcP activity and compared PlcP substrate specificities in PlcP enzymes from two model marine bacteria from the marine Roseobacter clade and the SAR11 clade. Our data provide new insights into the regulation of lipid remodeling in these marine bacteria.

Screening new Clostridium strains that can efficiently utilize lignocellulose to produce hydrogen is extremely important for dark fermentative hydrogen production. In this study, a mesophilic hydrogen-producing bacterium, identified as Clostridium populeti FZ10, was newly isolated from compost acclimated by microcrystalline cellulose. The strain could produce hydrogen from various cellulosic substrates. The performances of hydrogen production from microcrystalline cellulose (MCC) and corn stalk (CS) were especially investigated. The maximum hydrogen yield and hydrogen production rate from MCC were 177.5 ± 4.8 mL/g and 7.7 ± 0.2 mL·g⁻¹·h⁻¹, respectively. Furthermore, scanning electron microscopy (SEM) images showed that the structure of CS was destroyed after fermentation, which could be attributed to the presence of exoglucanase, endoglucanase, β-glucosidase and xylanase produced by Clostridium populeti FZ10. The maximum hydrogen yield and hydrogen production rate from CS were 92.5 ± 3.7 mL/g and 5.9 ± 0.2 mL·g⁻¹·h⁻¹,respectively, with a cellulose degradation of 47.2 ± 2.3% and a hemicellulose degradation of 58.1 ± 2.0%. This study demonstrates that Clostridium populeti FZ10 is an ideal candidate for directly converting lignocellulose into biohydrogen under mesophilic conditions. The discovery of strain C. populeti FZ10 has special significance in the field of bioenergy.

The aim of this study was to develop an ionic liquid (IL) system for the enzymatic resolution of racemic ibuprofen ethyl ester to produce (S)-ibuprofen. Nineteen ILs were selected for use in buffer systems to investigate the effects of ILs as cosolvents for the production of (S)-ibuprofen using thermostable esterase (EST10) from Thermotoga maritima. Analysis of the catalytic efficiency and conformation of EST10 showed that [OmPy][BF₄] was the best medium for the EST10-catalyzed production of (S)-ibuprofen. The maximum degree of conversion degree (47.4%), enantiomeric excess of (S)-ibuprofen (96.6%) and enantiomeric ratio of EST10 (177.0) were achieved with an EST10 concentration of 15 mg/mL, racemic ibuprofen ethyl ester concentration of 150 mM, at 75 °C , with a reaction time of 10 h. The reaction time needed to achieve the highest yield of (S)-ibuprofen was decreased from 24 h to 10 h. These results are relevant to the proposed application of ILs as solvents for the EST10-catalyzed production of (S)-ibuprofen.

This study investigated the feasibility of producing L-lactic acid (LA) from dry corn stalk (DCS) that was pretreated by ensiling by an anaerobic microbial community consisting of Bacillus coagulans, Lactobacillus fermentum, and Enterococcus durans. After 28 days of ensiling, the LA and acetic acid content in the microsilage was 2.04 ± 0.08% and 0.38 ± 0.01%, respectively, and the pH was 4.47 ± 0.13. Enterococcus and Lactobacillus became the dominant microbiota during the ensiling process. Twenty-eight-day-old microsilage was then subjected to fermentation by B. coagulans to produce LA in a simultaneous saccharification and co-fermentation process. The enzymatic hydrolysis yield reached >96%. The maximal concentration of LA reached 18.54 ± 0.52 g/L with a substrate concentration of 5%, where the yield of LA was 0.31 ± 0.01 g/g DCS and the optical purity of the product LA was >97%. Anaerobic ensiling is viable for the pretreatment of biomass for the production of value-added chemicals.

The bilayer formed by membrane lipids serves as the containment unit for living microbial cells. In the marine environment, it has been firmly established that phytoplankton and heterotrophic bacteria can substitute phospholipids with nonphosphorus sugar-containing glycoglycerolipids in response to phosphorus limitation.