An emerging simple and effective approach to increase the productivity of thraustochytrids microbial lipids by regulating glycolysis process and triacylglycerols’ decomposition

Background The oleaginous microorganism Schizochytrium sp. is widely used in scientific research and commercial lipid production processes. However, low glucose-to-lipid conversion rate (GLCR) and low lipid productivity of Schizochytrium sp. restrict the feasibility of its use. Results Orlistat is a lipase inhibitor, which avoids triacylglycerols (TAGs) from hydrolysis by lipase. TAGs are the main storage forms of fatty acids in Schizochytrium sp. In this study, the usage of orlistat increased the GLCR by 21.88% in the middle stage of fermentation. Whereas the productivity of lipid increased 1.34 times reaching 0.73 g/L/h, the saturated fatty acid and polyunsaturated fatty acid yield increased from 21.2 and 39.1 to 34.9 and 48.5 g/L, respectively, indicating the advantages of using a lipase inhibitor in microbial lipids fermentation. Similarly, the system was also successful in Thraustochytrid Aurantiochytrium. The metabolic regulatory mechanisms stimulated by orlistat in Schizochytrium sp. were further investigated using transcriptomics and metabolomics. The results showed that orlistat redistributed carbon allocation and enhanced the energy supply when inhibiting the TAGs’ degradation pathway. Therefore, lipase in Schizochytrium sp. prefers to hydrolyze saturated fatty acid TAGs into the β-oxidation pathway. Conclusions This study provides a simple and effective approach to improve lipid production, and makes us understand the mechanism of lipid accumulation and decomposition in Schizochytrium sp., offering new guidance for the exploitation of oleaginous microorganisms.

Pancreatic Lipase Inhibitory Activity of Endophytic Actinobacteria from Rhododendron spp.

Antiobesity medication is available as therapeutic compounds that can reduce fat digestion by the inhibition of pancreatic lipase. Actinobacteria have the potency as source of bioactive compounds with various biological function including as pancreatic lipase inhibitor. However, the potency of endophytic actinobacteria from Rhododendron spp. as source of pancreatic lipase inhibitor producer has not been reported yet. The aim of this study was to examine the potential of pancreatic lipase inhibitory activity of 23 endophytic actinobacteria from Rhododendron spp.; to characterize their colony based on morphology and molecular analysis. Screening test of pancreatic lipase inhibitor was conducted using the supernatant of endophytic actinobacteria, lipase pancreatic porcine (L3126) and p-nitrophenyl butyrate. The supernatant of selected isolates was extracted using ethyl acetate. The result showed that various inhibitory activities ranging between 0.00 until 91.69%. There were 11 out of 23 isolates that have potential as pancreatic inhibitor. Amongst them, the extract of four selected isolates, i.e. RZP 1.3, RSSB 3.2, RSS 2.1, and RJB F3.2 demonstrated inhibitory percentage of more than 80%. The RJB F3.2 extract showed to have IC50 value by 431.48 µg mL-1 compared to control, i.e. Xenical (89.07 µg mL-1). Phytochemical analysis exhibited that the extract of the selected isolates contained alkaloid which may function as pancreatic lipase inhibitor. Based on the morphological character, the selected isolates have various morphological colonies and 16S rRNA gene sequence revealed the sequence homology to Streptomyces spp. The data clearly indicate that endophytic actinobacteria from Rhododendron spp. have potency as pancreatic lipase inhibitor producer and further studies could be explored for the development of antiobesity agent.

Proteinous pancreatic lipase inhibitor is responsible for the antiobesity effect of young barley (Hordeum vulgare L.) leaf extract

Young barley leaves (Hordeum vulgare L.) have various health effects and are employed as an ingredient in the production of health-promoting foods. Promoting antiobesity is one such health effect; however, the mechanism and bioactive compounds are unclear. In this research, young barley leaf extract (YB) was demonstrated to possess pancreatic lipase inhibitory activity. The addition of YB to a high-fat diet in mice increased fecal lipid content, indicating reduced absorption of lipids as the mechanism underlying antiobesity effect. The investigation of bioactive compounds in YB resulted in the identification of fructose–bisphosphate aldolase as a proteinous lipase inhibitor. Maximum inhibition of the protein was 45%, but inhibition was displayed at a concentration as low as 16 ng/mL, which is a characteristic inhibition compared with other reported proteinous lipase inhibitors.