Synthesis of 2-hydroxy acid from 2-amino acid by Clostridium butyricum

Isolation and Synthesis of Misszrtine A: A Novel Indole Alkaloid From Marine Sponge-Associated Aspergillus sp. SCSIO XWS03F03

A novel indole alkaloid, misszrtine A (1), was isolated from marine sponge-derived fungus Aspergillus sp. SCSIO XWS03F03. The planar structure of 1 was assigned by analysis of spectroscopic data, the absolute configuration of which was unambiguously determined by total synthesis. Compound 1 represents the first example of N-isopentenyl tryptophan methyl ester with a phenylpropanoic amide arm, which exhibited a potent antagonistic activity on HL60 (IC₅₀ = 3.1 μM) and LNCaP (IC₅₀ = 4.9 μM) cell lines. Bioactivity evaluation reveals that functional group on indole nitrogen of 1 has a great effect on its cytotoxity, which provides a mean to probe the structure-activity relationships of 1.

Biorefining of protein waste for production of sustainable fuels and chemicals

To mitigate the climate change caused by CO₂ emission, the global incentive to the low-carbon alternatives as replacement of fossil fuel-derived products continuously expands the need for renewable feedstock. There will be accompanied by the generation of enormous protein waste as a result. The economical viability of the biorefinery platform can be realized once the surplus protein waste is recycled in a circular economy scenario. In this context, the present review focuses on the current development of biotechnology with the emphasis on biotransformation and metabolic engineering to refine protein-derived amino acids for production of fuels and chemicals. Its scope starts with the explosion of potential feedstock sources rich in protein waste. The availability of techniques is applied for purification and hydrolysis of various feedstock proteins to amino acids. Useful lessons are leaned from the microbial catabolism of amino acids and lay a foundation for the development of the protein-based biotechnology. At last, the future perspective of the biorefinery scheme based on protein waste is discussed associated with remarks on possible solutions to overcome the technical bottlenecks.

Biocontrolled formal inversion or retention of L-α-amino acids to enantiopure (R)- or (S)-hydroxyacids

Natural L-α-amino acids and L-norleucine were transformed to the corresponding α-hydroxy acids by formal biocatalytic inversion or retention of absolute configuration. The one-pot transformation was achieved by a concurrent oxidation reduction cascade in aqueous media. A representative panel of enantiopure (R)- and (S)-2-hydroxy acids possessing aliphatic, aromatic and heteroaromatic moieties were isolated in high yield (67-85 %) and enantiopure form (>99 % ee) without requiring chromatographic purification.

Cleavage of L-leucine-containing dipeptides by Clostridium butyricum

The ability of Clostridium butyricum cultures to hydrolyze three L-leucine-containing dipeptides (Leu-Leu, Leu-Gly and Gly-Leu) in a synthetic minimal medium is demonstrated by using gas chromatography coupled with mass spectrometry. The 13C nuclear magnetic resonance and a labeled dipeptide L-[1-13C]Leu-Gly were used to confirm this activity.