RESUMEN
We investigated butanol recovery by pervaporation separation, using a silicalite-1 membrane, from batch cultures of butanol-producing Clostridium beijerinckii SBP2 grown on sweet sorghum juice as a fermentation medium. The pervaporation system yielded 73% (w/v) butanol from intact feed cultures containing 1% (w/v) butanol, and had a butanol permeation flux of 11 g m(-2) h(-1). Upon neutralization and activated charcoal treatment of the feed cultures, butanol yield and total flux increased to 82% (w/v) and 40 g m(-2) h(-1), respectively. This system is applicable to refining processes for practical biobutanol production from a promising energy crop, sweet sorghum.
Asunto(s)
1-Butanol/aislamiento & purificación , 1-Butanol/metabolismo , Acetona/metabolismo , Clostridium beijerinckii/metabolismo , Etanol/metabolismo , Fermentación , Membranas Artificiales , Sorghum/química , Técnicas de Cultivo Celular por Lotes , Carbón Orgánico , Clostridium beijerinckii/crecimiento & desarrollo , VolatilizaciónRESUMEN
Enterococcus faecium No. 78 (PNCM-BIOTECH 10375) isolated from puto, a type of fermented rice in the Philippines was used to produce lactic acid in repeated batch fermentation mode. Enzymatically liquefied sago starch was used as the sole carbon source, since sago (Metroxylon spp) is a sustainable crop for industrial exploitation. Liquefied sago starch was inoculated with E. faecium to perform the saccharification and fermentation processes simultaneously. Results demonstrated that E. faecium was reused for 11 fermentation cycles with an average lactic acid yield of 36.3 ± 4.71 g/l. The lactic acid production was superior to that of simple batch mode and continuous fermentation in terms of lactic acid concentration. An un-dissociated lactic acid concentration of 1.15 mM affected the productivity of the cells. Work is in progress to maintain and increase the usability of the cells over higher fermentation cycles.
RESUMEN
Ethanol was efficiently produced from three varieties of sweet sorghum using repeated-batch fermentation without pasteurization or acidification. Saccharomyces cerevisiae cells could be recycled in 16 cycles of the fermentation process with good ethanol yields. This technique would make it possible to use a broader range of sweet sorghum varieties for ethanol production.
Asunto(s)
Biocombustibles , Etanol/metabolismo , Fermentación , Sorghum/metabolismo , Saccharomyces cerevisiae/metabolismoRESUMEN
A new fungal isolate that grows endophytically in sweet sorghum was identified as Helminthosporium velutinum Link ex Ficinus & Schubert. Light-microscopy of cross-sections of colonized sweet sorghum roots showed that the intercellular, pigmented hyphae of the fungus was mostly limited to the epidermal layer and formed outer mantle-like structures. This endophyte has the ability to significantly increase sweet sorghum biomass. This is the first report of Helminthosporium as an endophyte and could help realize sustainable the biomass production for biofuel purposes.