Solid state fermentation was carried out for the production of spores from Trichoderma harzianum No 53 using sugar cane bagasse pith as solid matrix and sugar cane molasses as carbon and energy source. Different nitrogen sources such as urea, (NH4)2SO4 , NH4H2PO4 and (NH4)2HPO4 were added in the media to test their effect on spores production. Among these, urea was found most useful that resulted high no of spores (1x10(9)/gDM). The influence of temperature and initial moisture of the substrate was studied through a 2² experimental plan design. No statistical differences were found within the range of 30-35ºC and 60-70% for temperature and moisture respectively. The biotechnological parameters of the process were derived from the Oxygen Uptake Rate (OUR) pattern, which corresponded to the order of 10(9)spores/g moist material. The specific growth rate, maintenance coefficient and the yield based on O2 consumption were 0.108 h-1, 0.001 g.O2/g.biomass.h and 2.7 g biomass/g O2 consumed, respectively. Esporos de Tricoderma harzianum Nº 53 foram produzidos por fermentação no estado sólido (FES) utilizando bagaço de cana como suporte e melaço de cana como fonte de carbono. Diferentes fontes de nitrogênio foram testadas (uréia, (NH4)2 SO4 , NH4H2PO4 e (NH4)2HPO4 ) na produção de esporos. As mais elevadas concentrações de esporos (10(9) esporos/g de suporte úmido) foram obtidas utilizando a uréia como fonte de nitrogênio. O efeito da temperatura e umidade inicial foram estudadas através da utilização da planificação experimental utilizando um modelo 2². Não foi encontrada diferença estatística na produção de esporos na faixa de temperatura compreendida entre 30-35 ° C e umidade inicial de 60-70%. Os parâmetros biotecnológicos foram determinados através da taxa de oxigênio consumido (OUR) correspondente a uma produção de 10(9) esporos/g de suporte úmido. A taxa de crescimento especifico, coeficiente de manutenção e rendimento foram calculados em função do O2 consumido, cujos valores foram 0.108 h-1 , 0.001 g O2/g biomassa/h e 2.7 g biomassa/g O2 consumido respectivamente
Ethanol biofiltration was studied in a 0.1651 packed bed reactor filled with sugar cane bagasse complemented with mineral medium and inoculated with Candida utilis. The main objective was to improve the elimination capacity of the system by adding salts to the solid medium. The biofilter was operated for one month, varying both the inlet ethanol concentration (7.6-16.5 g m(-3) and the airflow rate (1.61-2.50 x 10(-3) m3 h(-1)). Removal efficiency (RE) of 100% was attained at ethanol loads ranging from 74.2 to 250 g h(-1) m(-3). When the RE decreased, acetaldehyde and ethyl acetate appeared in the outlet stream; adding mineral salts restored a 100% RE. Both ammonium sulfate and ammonia were assimilated by the yeast (conversion yield of nitrogen from the N-source to biomass of 75%), but only ammonia restored the pH of the medium to a value adequate for efficient biofiltration (7.7). Fifty seven percent of the carbon from ethanol was converted into CO2, and 8.7% into biomass. Final yeast population was 7 x 10(9) cells g(-1) dry matter, corresponding to 56 mg protein g(-1) dry matter, which offers potential to also use the protein enriched bagasse as feed.
Ethanol has been reported to be a gaseous pollutant, originating from the agricultural industry.Interest in its biodegradation has increased over the last two decades. Most of the current studies have focused on its elimination by mixed cultures. This study is part of a broader project intended to utilize Can&& ufilis strains for gaseous ethanol elimination and to eventudy bioconvert them into biomass and/or volatile metabolites. We present here the study of six strains (one from the ATCC and five from the ICIDCA collection) cultivated in a liquid medium, with initial ethanol concentrations of 16 g/l and 3261. At 16 61, a maximum ethanol elimination rate of 0.13 g/l x h was obtained in four of the six strains (ATCC 9950, U375-1. U375-5 and U375-10). This rate increased to 0.21 g/l x h with an initial ethanol concentration of 32 g/l. The U375-5 strain was the best biomass producer (3.3 g/l) at 32 g/l. while the highest ethyl acetate production (0.80 g/l) was obtained with the Ln75-1 strain. The U375-25 and U375-26 strains which showed very low ethyl acetate production were, by way of contrast, efficient acetaldehyde producers, with 0.54 gA and 0.66 g/l measured in the broth. While biomass production reached its maximum after two days of culture, the production of acetic acid and ethyl acetate continued during the third day. The results for biomass and metabolite production obtained with the ICIDCA collection strains (U375-1, U375-5 and U375-10) were better than those obtained with the ATCC 9950 strain, although the latter often has been reported to be particularly suitable for metabolite production.
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