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A novel marine hydrogen- and sulfur-oxidizing bacterium, designated strain S2-6 T, was isolated from the deep-sea sediment samples at the Longqi hydrothermal system, southwestern Indian Ocean. Cells were Gram-stain-negative, motile, short rods with a single polar flagellum. Growth was observed at 10–45 °C (optimum 33 °C), pH 5.0–8.0 (optimum pH 7.0) and 1.5 to 6.0% (w/v) NaCl with an optimum at 3.0% (w/v). The isolate was an obligate chemolithoautotroph capable of growth using thiosulfate, tetrathionate, elemental sulfur or sodium sulfide as the energy source, and oxygen or nitrate as the sole electron acceptor. When hydrogen was used as the energy source, strain S2-6 T could respire oxygen, nitrate or element sulfur. The major cellular fatty acids of strain S2-6 T were summed feature 3 (C16:1ω7c and/or C16:1ω6c), C16:0 and summed feature 8 (C18:1ω7c and/or C18:1ω6c). The total size of its genome was 2,320,257 bp and the genomic DNA G + C content was 37.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences and core genes showed that the novel isolate belonged to the genus Sulfurimonas and was most closely related to Sulfurimonas paralvinellae GO25T (96.8% sequence identity) and Sulfurimonas autotrophica OK10T (95.8% sequence identity). The average nucleotide identity and DNA-DNA hybridization values between strain S2-6 T and S. paralvinellae GO25T and S. autotrophica OK10T were 74.6%-81.2% and 19.1%-24.6%, respectively. Based on the polyphase taxonomical data, strain S2-6 T represents a novel species of the genus Sulfurimonas, for which the name Sulfurimonas sediminis sp. nov. is proposed, with the type strain S2-6 T (= MCCC 1A14513T = KCTC 15854 T). [ABSTRACT FROM AUTHOR]

Previously, AoamyA, the alpha amylase-encoding gene from Aspergillus oryzae, was heterologously expressed in Monascus ruber CICC41233 to promote starch hydrolysis and increase the production of Monascus pigments. The target of this study is to screen the effective alpha-amylases from M. ruber for starch fast degradation and investigated for Monascus pigments production. The 13 types of predicted alpha-amylases in the M. ruber NRRL1597 genome were divided into four classes based on EC number and into five groups based on the glycoside hydrolase sub-family. The predicted alpha-amylases MrAMY1 (protein ID 440333) and MrAMY2 (protein ID 324551) showed the closest match with AOamyA by phylogenetic analysis. The genes encoding alpha-amylase, Mramy1and Mramy2, were cloned from M. ruber CICC41233. However, the gene sequence of Mramy1 from M. ruber CICC41233 differed from that of M.ruber NRRL1597 in the length of the intron sequence. Furthermore, the Mramy1-overexpressed strain M.ruber 440333-6A completely degraded the starch of rice grain in 2 d; in contrast, starch (40.32 mg/mL) remained when rice grain was incubated with the Mramy2-overexpressed strain, M. ruber 324551-D even after 2 d, while 45.43 mg/mL and 10.48 mg/mL starch remained after 2 d and 6 d, respectively, in wild type M. ruber CICC41233. Compared to that of M. ruber CICC41233, the total Monascus pigments and ethanol-soluble pigments in M.ruber 440333-6A increased by 71.69% and 119.33% after 6d, respectively; however, it decreased by 21.40%and 26.58% after 6d, respectively, in M. ruber 324551-D. This study demonstrated that alpha-amylase MrAMY1 was superior to MrAMY2, as it effectively degraded the starch of rice grain and enhanced Monascus pigments production. [ABSTRACT FROM AUTHOR]

To investigate the relationship between starch hydrolysis and Monascus pigments (MPs) production, the α-amylase gene (AOamyA) from Aspergillus oryzae was heterologously expressed in Monascus ruber CICC41233, and we obtained a positive transformant named Monascus ruber Amy9. In M. ruber Amy9, the α-amylase activities were 6.65- and 4.26-fold higher at 72 h and 144 h, respectively, than those in the parent strain with the glucose as solo carbon medium. Surprisingly, in the MPs fermentation medium with rice powder as solo material, M. ruber Amy9 completely degraded starch at 48 h, while 43.93 and 7.29 mg/mL starch remained at 48 and 144 h, respectively, in the parent strain. Monascus ruber Amy9 accelerated starch hydrolysis, which enhanced biomass and also increased total MPs by 132% after 144 h. Compared with M. ruber CICC41233, the relative gene expression levels, as determined by a quantitative real-time polymerase chain reaction analysis, of acl2 encoding ATP-citrate lyase subunit 2, pks encoding polyketide synthase, and fasB encoding the fatty acid synthase beta subunit increased by 33.14, 145.18, and 32.15%, respectively, after 144 h in M. ruber Amy9. The up-regulated expression of these key genes in MPs synthesis contributed to the large increase in MPs production. This interesting work provided us with a new idea and a new target for the study of the MPs production. [ABSTRACT FROM AUTHOR]