Novel α-Amylase Inhibitor Hemi-Pyocyanin Produced by Microbial Conversion of Chitinous Discards

Abstract

α-Amylase inhibitors (aAIs) have been applied for the efficient management of type 2 diabetes. The aim of this study was to search for potential aAIs produced by microbial fermentation. Among various bacterial strains, Pseudomonas aeruginosa TUN03 was found to be a potential aAI-producing strain, and shrimp heads powder (SHP) was screened as the most suitable C/N source for fermentation. P. aeruginosa TUN03 exhibited the highest aAIs productivity (3100 U/mL) in the medium containing 1.5% SHP with an initial pH of 7–7.5, and fermentation was performed at 27.5 °C for two days. Further, aAI compounds were investigated for scaled-up production in a 14 L-bioreactor system. The results revealed a high yield (4200 U/mL) in a much shorter fermentation time (12 h) compared to fermentation in flasks. Bioactivity-guided purification resulted in the isolation of one major target compound, identified as hemi-pyocyanin (HPC) via gas chromatography-mass spectrometry and nuclear magnetic resonance. Its purity was analyzed by high-performance liquid chromatography. HPC demonstrated potent α-amylase inhibitory activity comparable to that of acarbose, a commercial antidiabetic drug. Notably, HPC was determined as a new aAI. The docking study indicated that HPC inhibits α-amylase by binding to amino acid Arg421 at the biding site on enzyme α-amylase with good binding energy (−9.3 kcal/mol) and creating two linkages of H-acceptors.

Bioconversion of a Peanut Oil Processing By-Product into a Novel α-Glucosidase Inhibitor: Hemi-Pyocyanin

“…The yellow compound was purified according to the method presented in our earlier report [33] and this purification protocol is summarized in Figure 5.…”

“…As shown by the data presented in Figure 6, the purified HPC appeared with a single peak at the retention time of 3.317 min. For comparison purposes, the reference HPC compound obtained in our previous report [33] also underwent HPLC analysis. This reference compound also appeared at the retention time of 3.323 min during HPLC fingerprinting (Figure 6), approximately similar to that of the HPC purified in this study (RT = 3.317 min).…”

“…In our previous work [33], HPC was investigated as the main secondary metabolite produced by TUN03 strain fermentation. In this study, we explored the potential use of organic waste for the eco-friendly production of HPC via P. aeruginosa TUN03 fermentation.…”

Novel Black Pepper Antinematode Compounds Produced by Bacillus velezensis RB.EK7 Conversion of Organic Wastes

“…The virtual study protocol was done according to the method presented in our earlier works [14,21,22] with three typical steps as below:…”

“…In the docking simulations, the RMSD and docking score (DS, binding energy) were considered important parameters to confirm the interaction and whether the binding energy of the ligand toward the protein enzyme is significant. When a ligand (compound inhibitor) interacts and binds to a protein enzyme with the DS and RMSD values of lower than −3.20 kcal/mol and 3.0 Å, respectively, the compound is considered a potential inhibitor [21][22]26,42]. As shown in Table 2, both ligands, thymine, and hexahydropyrrolo [1,2-a] pyrazine-1,4-dione interacted with the protein AchE with RMSD and DS values in the range of 1.02 Å to 1.35 Å, and -6.89 kcal/mol to -7.07 kcal/mol, respectively, significantly less than 3.0 Å and −3.20 kcal/mol.…”