Light-enhanced bioaccumulation of molybdenum by nitrogen-deprived recombinant anoxygenic photosynthetic bacterium Rhodopseudomonas palustris

• Published in: Bioscience, biotechnology, and biochemistry Vol. 80; no. 2; pp. 407 - 413
• Main Authors: Naito, Taki, Sachuronggui, Ueki, Masayoshi, Maeda, Isamu
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 01.02.2016
• Subjects: Ammonium Compounds - metabolism; Ammonium Compounds - pharmacology; Anaerobiosis; Apoproteins - genetics; Apoproteins - metabolism; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Gene Expression Regulation, Bacterial; Genetic Engineering; Light; ModE; molybdenum; Molybdenum - metabolism; Molybdoferredoxin - genetics; Molybdoferredoxin - metabolism; Nitrogen - deficiency; nitrogenase; photosynthetic bacteria; Rhodopseudomonas - genetics; Rhodopseudomonas - metabolism; Rhodopseudomonas - radiation effects; Transcription Factors - genetics; Transcription Factors - metabolism; Transcription, Genetic; photosynthetic bacteria; ModE; molybdenum; nitrogenase
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1080/09168451.2015.1086260

As molybdenum (Mo) is an indispensable metal for plant nitrogen metabolisms, accumulation of dissolved Mo into bacterial cells may connect to the development of bacterial fertilizers that promote plant growth. In order to enhance Mo bioaccumulation, nitrogen removal and light illumination were examined in anoxygenic photosynthetic bacteria (APB) because APB possess Mo nitrogenase whose synthesis is strictly regulated by ammonium ion concentration. In addition, an APB, Rhodopseudomonas palustris, transformed with a gene encoding Mo-responsive transcriptional regulator ModE was constructed. Mo content was most markedly enhanced by the removal of ammonium ion from medium and light illumination while their effects on other metal contents were limited. Increases in contents of trace metals including Mo by the genetic modification were observed. Thus, these results demonstrated an effective way to enrich Mo in the bacterial cells by the culture conditions and genetic modification. Mo content was specifically enhanced in N-deprived photosynthetic bacterium harboring a gene coding Mo-binding protein (FL, full-length; CT, Mo-binding domain; EV, vector).