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The nitrate metabolism in the actinomycete Streptomyces antibioticus shows an unique feature in that it generates gaseous nitrogen and nitrous oxide from nitrate via both denitrification and codenitrification. Data suggest that the latter process is dominant.

Multiple chitinases have been observed in hyphae of filamentous fungi which are thought to have various hyphal growth function. The primary structure of chitinase III from Rhizopus oligosporous, a fungus, is reported. The deduced amino acid sequence of chi3 was similar to bacterial chitinases from mycoparasitic fungi. Chi3 was found to be transcribed during hyphal growth, suggesting a function during morphogenesis.

Two Rhizopus oligosporus chitinases, designated chitinase I and chitinase II, were purified and their genes isolated. The molecular masses of the deglycosylated purified chitinase I and II were 44.5 and 46.5 kDa, respectively. The primary structures of the products of the chi1 and chi2 genes are divided into the signal sequence, the catalytic domain, the Ser- and Thr-rich domain, the chitin-binding domain and the C-terminal domain. Furthermore, it was found that the molecular masses deduced from the nucleotide sequences for both genes were almost the same (53. 987 kDa for chi1 and 54.258 kDa for chi2).

Production of bioplastics from renewable biological resources is a prerequisite for the development of a circular and sustainable society. Current bioplastics are mostly heat‐sensitive aliphatic polymers, requiring thermoresistant aromatic bioplastics. Herein, 3‐amino‐4‐hydroxybenzoic acid (AHBA) and 4‐aminobenzoic acid (ABA) are produced from kraft pulp, an inedible cellulosic feedstock, using metabolically engineered bacteria. AHBA is chemically converted to 3,4‐diaminobenzoic acid (DABA); subsequently, poly(2,5‐benzimidazole) is obtained by the polycondensation of DABA and processed into an ultrahigh thermoresistant film. The copolymerization of DABA with a small amount of ABA dramatically increases the degradation temperatures of the resulting films (over 740 °C) to yield the most thermoresistant plastic on record. Density functional theory calculations indicate that the incorporation of ABA strengthens the interchain hydrogen bonds between aromatic imidazole rings. Thus, an alternative organic molecular design is proposed for thermoresistant plastics without using heavy inorganics, although continuous aromatic heterocycles are widely considered ideal for polymer thermoresistance. This innovative macromolecular design increases thermoresistance and can be widely applied to well‐processable plastics for the production of lightweight materials and is expected to contribute to the development of a more sustainable society. [ABSTRACT FROM AUTHOR]

The denitrification mechanism in actinomycetes was determined through the purification of nitrite reductase and azurin from the Streptomyces thioluteus JCM 4844. Denitrification is a biological mechanism important in the nitrogen global cycle since it is involved in the nitrogen cycle that counteracts nitrogen fixation. It was revealed that actinomycetes transformed nitrite or nitrate to nitric oxide as a denitrification product. The greenhouse effect of nitric oxide was believed to be 200 times greater than that of carbon dioxide on a per-molecule basis.

The different physiochemical properties exhibited by the membrane vesicles (MVs) released by Pseudomonas aeruginosa during the exponential and stationary phases are described. The findings indicated that the properties of MVs are altered to readily interact with bacterial cells along with the growth transition in P. aeruginosa.

A study was conducted to examine the physiological significance of hypotoxic branched-chain amino acid production by Aspergillus nidulans and study the expression of the mechanism and properties of knockout strains of acetohydroxy acid synthase (AHAS)-encoding genes in the fungus A. nidulans. The results suggested that the hypoxic branched-chain amino acid synthesis is a unique alternative mechanism that functions in the absence of glucose-to-ethanol/lactate fermentation and oxygen respiration.

The denitrifying properties of Ochrobactrum anthropi are examined, where the strain YD50.2 has denitrified high levels of N[O.sub.2.sup.-] to dinitrogen under anaerobic conditions. The results have shown that Ochrobactrum anthropi YD50.2 has mechanisms that have produced tolerance to reactive nitrogen species (RNS).

Research has been conducted on aerobic denitrifiers producing low levels of nitrous oxide under aerobic conditions. The authors describe the isolation and characterization of these denitrifiers, and report that these strains produce less nitrous oxide under aerobic conditions.