RESUMO
A Gram-stain-positive, rod-shaped and endospore-forming bacterium, strain RC11T, isolated from ant nest soil collected from Udon Thani Province, Thailand was characterized in a taxonomic study based on a polyphasic approach. On the basis of 16S rRNA gene sequence analysis, strain RC11T was affiliated to the genus Paenibacillus and was closely related to Paenibacillus phyllosphaerae LMG 22192T with 98.1â% sequence similarity. Strain RC11T contained meso-diaminopimelic in the cell-wall peptidoglycan. The major menaquinone was MK-7. Anteiso-C15â:â0, iso-C16â:â0, anteiso-C17â:â0 and C16â:â0 were the predominant cellular fatty acids. Diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol were the major polar lipids. The DNA G+C content was 57.9 mol%. In addition, strain RC11T and P. phyllosphaerae LMG 22192T showed a low level of DNA-DNA relatedness (15.6-33.2â%). Therefore, strain RC11T represents a novel species of the genus Paenibacillus, for which the name Paenibacillus aurantiacus sp. nov. is proposed. The type strain is RC11T (=KCTC 33816T=LMG 29659T=TISTR 2452T).
Assuntos
Formigas , Paenibacillus/classificação , Filogenia , Microbiologia do Solo , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , Parede Celular/química , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Paenibacillus/genética , Paenibacillus/isolamento & purificação , Peptidoglicano/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , TailândiaRESUMO
Rice straw (RS) may serve as a low-cost biomass for the production of biofuels and biochemicals, but its native structure is resistant to enzymatic and microbial deconstruction. Therefore, an efficient pre-treatment method is required to modify crystalline cellulose to a more reactive amorphous form. This work investigated pre-treatments of rice straw involving size reduction (S) followed by either sodium hydroxide (NaOH) or diluted sulfuric acid (H2SO4) and liquid hot water (LHW). The shrinkage of the vascular bundles in the rice straw structure pre-treated with NaOH-LHW-S was higher than that with LHW-S and H2SO4-LHW-S pre-treatments. The highest levels of total fermentative products and residual sugars were obtained at the concentrations of 7.8 ± 0.2 and 2.1 ± 0.3 g/L, respectively, after fermentation by Clostridium cellulolyticum for NaOH-LHW-S pre-treated rice straw at 121 °C for 120 min. Overall, the combined physicochemical pre-treatment of RS led to improved microbial hydrolysis during cellulose degradation at the percentage of 85.5 ± 0.5.