Producción de invertasa por Aspergillus niger en fermentación líquida y fermentación sólida
The purpose of the present study was to compare the productivity of a fungal enzyme, invertase (sucrase o 13 fructo-furanosidase EC3.2.1.26) of Aspergillus niger grown in solid state fermentation (SSF) and submerged fermentation (SmF). Poliurethane foam was used as inert support in SSF experiments....
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2001 |
| País: | México |
| Institución: | Universidad Autónoma Metropolitana |
| Repositorio: | Repositorio Institucional de la UAM Iztapalapa |
| Idioma: | español |
| OAI Identifier: | oai:bindani.izt.uam.mx:6t053g530 |
| Acceso en línea: | https://doi.org/10.24275/uami.6t053g530 |
| Access Level: | acceso abierto |
| Palabra clave: | info:eu-repo/classification/LEM/Enzymes info:eu-repo/classification/LEM/Fermentación info:eu-repo/classification/LEM/Enzimas info:eu-repo/classification/LEM/Aspergillus niger info:eu-repo/classification/LEM/Fermentation info:eu-repo/classification/cti/3 |
| Sumario: | The purpose of the present study was to compare the productivity of a fungal enzyme, invertase (sucrase o 13 fructo-furanosidase EC3.2.1.26) of Aspergillus niger grown in solid state fermentation (SSF) and submerged fermentation (SmF). Poliurethane foam was used as inert support in SSF experiments. One of the objectives was to evaluate the effect of increasing initial sucrose concentrations as invertase inducer and sole carbon source. The following physiological parameters were evaluated: specific: growth rate (p.), maximal biomass (X,), biomass yields per substrate gram (YWS), enzyme yields per gram biomass (Y,) and culture productivity (P) from solid and submerged fermentations. A comparison of the above parameters was done to evaluate whether the higher productivity of SSF cultures is related to one or several of the growth and production parameters. The obtained results shown that in solid fermentation, biomass production was much higher than in liquid fermentation even when subsltrate consumption was comparable in both fermentation systems. This result was much more notable for higher substrate concentrations (higher than 50 g/l). Biomass yie1d.s were much higher in solid than in liquid state fermentation with a decreasing tendency as the substrate concentration was increased. Specific speed growth (p.) was higher to solid than in liquid fermentation at all sucrose concentrations tested. Invertase titers were higher in SSF than in SmF as well. At low sucrose concentrations (between 6.25 to 25 g/!) invertase productivity was comparable in both fermentation systems. However, at high initial sucrose concentration (100 g/¡) invertase productivity was 5 times higher in SSF than in SmF. Enzyme yield per gram of biomass (YEM) was much higher in SSF than in SmF. When sugar composition of the culture broth was analyzed, glucose and fructose were found to accumulate at higher concentrations in SmF than in SSF cultures. This can be related to slower growth in SmF cultures. Extracellular protease levels were measured in order to assert its effect on the stability of invertase activity in the cultures. Proteolytic activity was 6.5 times lower in SSF than in SmF. However these differences could not directly related to differences in invertase stability in the cultures. In liquid cultures, Aspergillus niger grew In the form of pellets. In SSF Aspergillus niger grew as disperse mycelia adhering in part o the polyurethane foam and growing in part as airea1 mycelia. Microscopic observation of liquid media within polyurethane cubes showed a liquid layer with thickness of 60 pm within the holes of polyurethane cubes. Knowing that the amount of liquid added per gram of polyurethane was 25 mi, a surface area of 4000 crn2 could be calculated. This means that in SSF the surface volume relation was 160 cm2/cm3, meanwhile in SmF this relation was 1 .O cm2/cm3. This represents a surface interchange 300 times bigger for SSF than for SmF cultures. According to these results, the following conclusions were supported: 1. Aspergillus niger grows faster, with higher biornass maximal and higher biomass yields in SSF than SmF 2. Invertase production is at least partially associated to biomass production In both culture systems. Therefore the higher enzyme productlvlty of SSF IS related to the higher and faster biomass production. 3. SSF cultures on PUF grows as dispersed mycelia with a big air space and a gas interchange space 160 times bigger in SSF thlan in SmF, meanwhlle SmF cultures grows as pellets with a very dense center. Therefore culture conditions and growth type uphold and difficult oxygen transfer in SSF and SmF respectlvely. |
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