Phycobiliproteins (derived from Arthrospira platensis) bioactive peptide extracts (PPE) possess multiple pharmacological effects in the mitigation of human metabolic disorders. The role of PPE in the treatment of diet-induced obesity and the understanding of the underlying mechanism between the gut microbiome and metabolic blood circulation for obese patients remains poorly understood. In this study, we showed that PPE attenuated obesity by reducing body weight, and ameliorated glucose and lipid indexes in serum. In particular, PPE is postulated to mitigate liver steatosis and insulin resistance. On the other hand, dietary treatment with PPE was found to “reconfigure” the gut microbiota in the way that the abundances were elevated for Akkermansia_muciniphila, beneficial Lactobacillus and Romboutsia, SCFA-producing species Faecalibacterium prausnitzii, Lachnospiraceae_bacterium, Clostridiales_bacterium, probiotics Clostridium sp., Enterococcus faecium, and Lactobacillus_johnsonii, while the abundance of Firmicutes was reduced and that of Bacteroidetes was increased to reverse the imbalance of Firmicutes/Bacteroidetes ratio. Finally, the metabolomics of circulating serum using UHPLC-MS/MS illustrated that PPE supplementation indeed promoted lipid metabolism in obese rats. As summary, it was seen that PPE reprogrammed the cell metabolism to prevent the aggravation of obesity. Our findings strongly support that PPE can be regarded as a potential therapeutic dietary supplement for obesity.

Bioconversion of lignocellulosic biomass is a highly promising alternative to rapidly reduce reliance on fossil fuels and greenhouse gas emissions. However, the use of lignocellulosic biomass is limited by the challenges of efficient degradation strategies. Given this need, Bacillus tropicus (B. tropicus) with cellulose degradation ability was isolated and screened from rotten dahlia. The strain efficiently utilized coconut oil cake (COC) to secrete 167.3 U/mL of cellulase activity. Electron microscopy results showed significant changes in the structure and properties of cellulose after treatment with B. tropicus, which increased the surface accessibility and the efficiency of the hydrolysis process. The functional group modification observed by Fourier transform infrared spectroscopy indicated the successful depolymerization of COC. The X-ray diffraction pattern showed that the crystallinity index increased from 44.8% to 48.2% due to the hydrolysis of the amorphous region in COC. The results of colorimetry also reveal an efficient hydrolysis process. A co-culture of B. tropicus and Saccharomyces cerevisiae was used to produce ethanol from COC waste, and the maximum ethanol yield was 4.2 g/L. The results of this work show that B. tropicus can be used to prepare biotechnology value-added products such as biofuels from lignocellulosic biomass, suggesting promising utility in biotechnology applications.

Arthrospira platensis phycobiliprotein peptide extracts (PPEs) exhibit potential mitigative effects on hepatic steatosis. However, the precise role of PPEs in addressing high-fat-induced nonalcoholic fatty liver disease (NAFLD), as well as the underlying mechanism, remains to be elucidated. In this study, NAFLD was induced in rats through a high-fat diet (HFD), and the rats were subsequently treated with PPEs for a duration of 10 weeks. The outcomes of this investigation demonstrate that PPE supplementation leads to a reduction in body weight gain, a decrease in the accumulation of lipid droplets within the liver tissues, alterations in hepatic lipid profile, regulation of lipolysis-related gene expression within white adipose tissues and modulation of intestinal metabolites. Notably, PPE supplementation exhibits a potential to alleviate liver damage by manipulating neutral lipid metabolism and phospholipid metabolism. Additionally, PPEs appear to enhance fat mobilization by up-regulating the gene expression levels of key factors such as HSL, TGL, UCP1 and UCP2. Furthermore, PPEs impact intestinal metabolites by reducing the levels of long-chain fatty acids while concurrently increasing the levels of short-chain fatty acids. The findings from this study unveil the potential of PPE intervention in ameliorating NAFLD through the modulation of hepatic lipid profile and the reinforcement of the fat mobilization of intestinal metabolites. Thus, PPEs exhibit noteworthy therapeutic effects in the context of NAFLD.