Genes enhancing lycopene production in Escherichia coli were identified through colorimetric screening of shot-gun library clones constructed with E. coli chromosomal DNA. These E. coli cells had been engineered to produce lycopene, a red-colored carotenoid, which enabled screening for genes that enhance lycopene production. Six clones with enhanced lycopene production were isolated. Among 13 genes in these clones, dxs, appY, crl, and rpoS were found to be involved in enhanced lycopene production. While dxs and rpoS have been already reported to enhance lycopene production, appY and crl have not. DXP (1-deoxy-D-xylulose-5-phosphate) synthase is encoded by dxs and participates in the rate-limiting step in the synthesis of isopentenyl pyrophosphate (IPP), a building block of lycopene. Sigma S factor, encoded by rpoS, regulates transcription of genes induced at the stationary phase. The appY and crl genes encode transcriptional regulators related to anaerobic energy metabolism and the formation of curli surface fibers, respectively. E. coli harboring appY plasmids produced 2.8 mg lycopene/g dry cell weight (DCW), the same amount obtained with dxs despite the fact that appY is not directly involved in the lycopene synthesis pathway. The co-expression of appY, crl, and rpoS with dxs synergistically enhanced lycopene production. The co-expression of appY with dxs produced eight times the amount of lycopene (4.7 mg/g DCW) that was produced without expression of both genes (0.6 mg/g DCW).

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Arenimonas oryziterrae sp. nov., isolated from a field of rice (Oryza sativa L.) managed under a notillage regime, and reclassification of Aspromonas composti as Arenimonas composti comb. nov. The taxonomic position of a novel bacterial strain, YC6267 T isolated from a field of rice (Oryza sativa L.) managed under a no-tillage regime in Jinju, Korea, was studied using a polyphasic taxonomic approach. Cells of the strain were Gram-stain-negative, rod-shaped and aerobic. It grew at 15-37 6C (optimum at 28 6C). Growth of the strain occurred between pH 5.0 and 10.0, with an optimum of pH 7.0-8.0. The G+C content of the total DNA was 65.8 mol%. The 16S rRNA gene sequence of the strain was most closely related to species of the genera Arenimonas (95.6-94.4 %) and Aspromonas (95.1 %), with ,95.0 % similarity to species of the genus Lysobacter and other genera of the family Xanthomonadaceae. Chemotaxonomic data (major quinone Q-8; major polar lipids phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol; and major fatty acids iso-C 15 : 0 , iso-C 14 : 0 , iso-C 16 : 0 , and iso-C 17 : 1 v9c) supported the affiliation of strain YC6267 T to the genus Arenimonas. Phylogenetic analysis based on 16S rRNA gene sequences and biochemical and physiological characteristics strongly supported the genotypic and phenotypic differentiation of strain YC6267 T from described species of the genus Arenimonas. Strain YC6267 T , therefore, represents a novel species, for which the name Arenimonas oryziterrae sp. nov. is proposed. The type strain is YC6267 T (5KCTC 22247 T 5DSM 21050 T ). In addition, the reclassification of Aspromonas composti as Arenimonas composti comb. nov. is proposed (type strain TR7-09 T 5KCTC 12666 T 5DSM 18010 T ). A common line of descent and a number of shared phenotypic traits support this reclassification.