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- Cost-effective bioethanol production at low content of nitrogen source from carob syrupPublication . Raposo, Sara; Sousa, Catarina; Rodrigues, B.; Lima-Costa, Maria Emília; Quintas, Célia; Rodrigues, F.Ethanol, as biofuel, has received great interest in the latest decades due to its potential as an alternative transport fuel. Nowadays, ethanol can be produced through fermentative processes, using sugar rich agricultural raw material and it may have a significant role in reducing environmental impact of fossil fuels.
- Carob pulp as raw material for production of the biocontrol agent P. agglomerans PBC-1Publication . Manso, Teresa; Nunes, Carla; Raposo, Sara; Lima-Costa, Maria EmíliaLarge-scale production has been the major obstacle to the success of many biopesticides. The spreading of microbial biocontrol agents against postharvest disease, as a safe and environmentally friendly alternative to synthetic fungicides, is quite dependent on their industrial mass production from low-cost raw materials. Considerable interest has been shown in using agricultural waste products and by-products from food industry as nitrogen and carbon sources. In this work, carob pulp aqueous extracts were used as carbon source in the production of the biocontrol agent Pantoea agglomerans PBC-1. Optimal sugar extraction was achieved at a solid/liquid ratio of 1:10 (w/v), at 25°C, for 1 h. Batch experiments were performed in shake flasks, at different concentrations and in stirred reactors at two initial inoculums concentrations, 106 and 107 cfu ml−1. The initial sugar concentration of 5 g l−1 allowed rapid growth (0.16 h−1) and high biomass productivity (0.28 g l−1 h−1) and was chosen as the value for use in stirred reactor experiments. After 22 and 32 h of fermentation the viable population reached was 3.2 × 109 and 6.2 × 109 cfu ml−1 in the fermenter inoculated at 106 cfu ml−1 and 2.7 × 109 and 6.7 × 109 cfu ml−1 in the bioreactor inoculated at 107 cfu ml−1. A 78% reduction of the pathogen incidence was achieved with PBC-1 at 1 × 108 cfu ml−1, grown in medium with carob extracts, on artificially wounded apples stored after 7 days at 25°C against P. expansum.
- The performance of an aerated stirred tank reactor on VHG batch fermentationsPublication . Raposo, Sara; Lima-Costa, Maria Emília; Rodrigues, B.The quest for new and renewable energy sources has greatly increased due to the depletion of fossil fuels reserves. Agro-food wastes appear as a cheap and renewable energy source that can contain great amounts of carbon to be transformed in bioethanol that can be used as additive to gasoline.
- Oleaginous microorganisms as sustainable feedstock for biodiesel productionPublication . Raposo, Sara; Pardão, J.; Lima-Costa, Maria EmíliaBiodiesel has had a considerable development in the past decade. High cost of oil feedstocks and problems associated with extensive cultivation of oleaginous plants to face growing market demand, competing with the agro-food industry for agricultural resources have limited production development. This situation has raised an intense global I&D effort in the search for raw materials alternative to oleaginous plants, which are the main energy resource for biodiesel production. Promising results have been obtained with oleaginous microorganisms, Rhodosporidium toruloides and Yarrowia lipolytica, being one of the potential sources of oils for biodiesel production.
- Mixing efficiency on plant cell growth and proteinase production in a stirred tank reactorPublication . Raposo, Sara; Lima-Costa, Maria EmíliaMixing efficiency is one of the most significant factors in bioprocess productivity. The major role of agitation is to improve broth homogenization, mass and heat transfer inside the bioreactors.
- Hydrolysis of lignocellulosic material of carob pulp in Batch, SSF and NSSF processes for ethanol productionPublication . Raposo, Sara; Sousa, Catarina; Rodrigues, B.; Caiado, Daniela; Lima-Costa, Maria EmíliaThe progress of technologies for fuel ethanol production is a priority, because this biofuel is one of the most important resources used as renewable energy sources.