4 research outputs found
Agro-food wastes for the release of phyto-chemicals and the production of enzymes by solid state fermentation using pleurotus ostreatus
No full textThe agro-food wastes represent a very important resource to recover chemical compounds with high added value that can be used in several industrial sectors and to the energetic production by biomass. This is a good method to value the agro-food wastes that are often undervalued. The hydrolitic demolition by lignocellulosic enzymes is one of the most studied approach for recovering phyto-chemicals from the cell wall of plants. Enzymes are perfect to this role, because they can be used in blind conditions resulting cheap and profitable. In this study, the concentration of reducing sugar (glucose) and total polyphenols (catechin), released in solution after the hydrolysis with lignocellulosic enzymes, were determined. The enzymes (extract enzymes) used are previously obtained, by growing the fungus Pleurotus ostreatus in solid state fermentations in presence of four separated agro-food wastes: grape stalks, grape seed, wheat straw and wheat bran. For the hydrolysis, the same biomass was used as substrates doing different combinations of substrate and enzymes extract (from different sources). The enzyme extracts from grapes stalks and wheat bran promoted the release of reducing sugars that were naturally rich in cellulase, pectinase xylanase activities. The wheat bran was the only matrix able to be hydrolyzed by all the enzyme extracts, probably due to the fact that its arabinoxylan structures are hydrolysable from the xylanase activities found in all the enzyme extracts. The increases on the polyphenols concentration during the hydrolytic reaction in oenological wastes were observed in the matrices rich in polyphenols such as grape seed and grape straw, even if the enzyme from the wheat bran was able to increase the content of polyphenols of 84 % compared to the initial one
Production of enzymes from rice husks and wheat straw in solid state fermentation
No full textIn Europe, the agricultural wastes represent a significant potential for the development of biorefineries in different sectors such as cereals. The residues from the processing of grains are about 11 million tons/year of dry basis (Di Biasi et al., 1997). Recovery of phytochemicals as well as the energetic valorization of the plant matrixes needs the demolition of the wall cell plants. Over the past 30 years, it has become clear that research on the degradation of lignocellulose by fungi may lead to other industrial applications (Crawford and Crawford, 1980). Hydrolitic demolition by lignocellulosic enzymes is one of the most studied approach. In recent years, SSF has received more and more interest from researchers, since several studies for enzymes (Pandey et al., 1999), flavours (Ferron et al., 1996), colourants (Johns and Stuart, 1991) and other substances of interest to the food industry have shown that SSF can give higher yields (Tsuchiya et al., 1994) or better product characteristics than submerged fermentation (SmF) (Acuña-Argüelles et al, 1995). Using of agro-industrial residues as substrates in SSF processes provides an alternative avenue and value-addition to these otherwise under- or non-utilized residues. Solid-state fermentation (SSF) has been defined as the fermentation process which involves solid matrix and is carried out in absence or near absence of freewater; although, the substrate must possess enough moisture to support growth and metabolism of the microorganism. The solid matrix could be either the source of nutrients or simply a support impregnated by the proper nutrients that allows the development of the microorganisms. Fungi and yeast were termed as suitable microorganisms for SSF according to the theoretical concept of water activity, where as bacteria have been considered unsuitable (Chinn et al., 2007). On one hand, by utilizing the low cost agricultural residues, SSF adds on to economic feasibility of the process (Robinson and Nigam, 2003) and on other hand it solves the problem of its disposal which otherwise cause pollution (Singhania et al., 2009).
Enzymes are among the most important industrial products obtained for human needs by microbial sources; in fact, a large number of industrial processes in the areas of industrial, environmental and food biotechnology utilize enzymes at some stage or the other. Solid state fermentation shows increasing interest for the production of enzymes, specially where the raw fermented waters may be used directly as enzyme sources (Pandey et al., 1999).
White rot fungi such as Pleurotus ostreatus produce a wide range of extracellular enzymes to degrade complex lignocellulosic substrates into soluble substances that can be used as nutrients (Giardina et al., 1995; Marzullo et al., 1995). The objective of this study is to induce the production of lignocellulosic enzymes through the growth Pleurotus ostreatus in solid state fermentation using agro-food wastes as substrates: rice husks and wheat stra
Effects on the enzymes production from different mixes of agro-food wastes
No full textThe solid state fermentation (SSF) is increasingly being used for the production of high value-added products using agro-food wastes as substrate. In fact, these residues which are available in large quantities and at low cost, have usable nutrients for the microorganism growth and seem to reproduce the natural habitat of filamentous fungi. In recent years, there have been significant additions to the science and engineering knowledge of SSF. Unlike systems SmF (Submerged Fermentation), the SSF are still able to achieve a high degree of development, mainly because of the problems associated with the beds solids, such as poor mixing of the materials and heat transfer. For this reason, we have been further studied the efficiency of the fermentation process through mechanical treatments of extrusion of the substrate (SSF dynamics), able to promote the availability of substrate, the exchange of oxygen on the surface, the activity produced and the recovery enzyme. In the presence of this process, was observed an increase on the production of several enzyme activities. In the third week of fermentation of grape stalks, the caffeoyl and feruloyl esterase showed a considerable increase of almost 3 and 4 times (respectively), with respect to the values obtained previously in static SSF. To increase the enzymatic activities produced by Pleurotus ostreatus in dynamic SSF (cellulase, xylanase, laccase, pectinase and arylesterase (caffeoyl esterase and feruloyl esterase)), we evaluated the effect of the mixes of agro-food wastes as substrates (grape stalks, grape seeds, and wheat bran) already previously used individually. The different enzymatic production by the P. ostreatus probably depends on the different chemical-physical composition of the substrates. Furthermore was noted that in the mixes of vegetable matrix, the different substrates can act both as inducers that as inhibitors of certain classes enzymatic, in relation to the specificity of each individual matrix. One of the examples is the presence of grape seeds or stalks in the mix, which seem to counteract the inductive action of the wheat bran in the synthesis of cellulase and xylanase
Sistemas para a produção de enzimas industriais para a valrização de descartes agroalimentares
No full textLa demolizione idrolitica delle pareti cellulari delle piante tramite enzimi lignocellulosici è quindi uno degli approcci più studiati della valorizzazione di scarti agricoli per il recupero di fitochimici di valore come secondary chemical building block per la chimica industriale. White rot fungi come il Pleurotus ostreatus producono una vasta gamma di enzimi extracellulari che degradano substrati lignocellulosici complessi in sostanze solubili per essere utilizzati come nutrienti.
In questo lavoro abbiamo studiato la produzione di diversi tipi di enzimi lignocellulosici quali cellulase, xilanase, pectinase, laccase, perossidase e arylesterase (caffeoilesterase e feruloilesterase), indotte dalla crescita di Pleurotus ostreatus in fermentazione allo stato solido (SSF) di sottoprodotti agroalimentari (graspi d’uva, vinaccioli, lolla di riso, paglia di grano e crusca di grano) come substrati.
Negli ultimi anni, SSF ha ricevuto sempre più interesse da parte dei ricercatori, dal momento che diversi studi per produzioni di enzimi, aromi, coloranti e altre sostanze di interesse per l' industria alimentare hanno dimostrato che SSF può dare rendimenti più elevati o migliorare le caratteristiche del prodotto rispetto alla fermentazione sommersa. L’utilizzo dei sottoprodotti agroalimentari come substrati nei processi SSF, fornisce una via alternativa e di valore, alternativa a questi residui altrimenti sotto/o non utilizzati.
L'efficienza del processo di fermentazione è stato ulteriormente studiato attraverso trattamenti meccanici di estrusione del substrato , in grado di promuovere il recupero dell’enzima e di aumentare l'attività prodotta.
Le attività enzimatiche prodotte dalla fermentazione sono strettamente dipendente della rimozione periodica degli enzimi prodotti.
Le diverse matrici vegetali utilizzate hanno presentato diversi fenomeni induttivi delle specifiche attività enzimatiche. I processi SSF hanno dimostrato una buona capacità di produrre enzimi extracellulari in grado di essere utilizzati successivamente nei processi idrolitici di bioraffinazione per la valorizzazione dei prodotti agroalimentari.The hydrolytic demolition of the plant cell walls by lignocellulosic enzymes is then one of the most studied approaches to the valorization of agricultural wastes for the recovery of high value phytochemicals such as secondary chemical building block for the industrial chemistry. White rot fungi such as Pleurotus ostreatus produce a wide range of extracellular enzymes to degrade complex lignocellulosic substrates into soluble substances that can be used as nutrients.
In this paper we have studied the production of different kinds of lignocellulosic enzymes such as cellulase, xylanase, pectinase, laccase, peroxidase and arylesterase (caffeoyl esterase and feruloyl esterase) induced by the growth of Pleurotus ostreatus in solid state fermentation (SSF) by agro-food wastes (such as grape stalks, grape seed, rice husk, wheat straw and wheat bran) as substrates.
In recent years, solid state fermentation (SSF) has received more and more interest from researchers, since several studies for enzymes, flavours, colorants and other substances of interest to the food industry have shown that SSF can give higher yields or better product characteristics than submerged fermentation. Using of agro-industrial residues as substrates in SSF processes provides an alternative avenue and value-addition to these otherwise under- or not-utilized residues.
The efficiency of the fermentation process has been further studied through mechanical treatments of extrusion of the substrate, able to promote the recovery enzyme and increase the activity produced.
The enzymatic activities produced by fermentation were strictly dependent to the periodic removal of the produced enzymes.
The different plant matrices used have presented different inductive phenomena for specific enzyme activities. The processes of SSF have shown a good ability to produce extracellular enzymes able to be used later in the hydrolytic processes of biorefining for the enhancement of integrated agro-food products
