Showing papers on "Solid-state fermentation published in 1997"

Pyrazine production by Bacillus subtilis in solid-state fermentation on soybeans

Abstract: 2,5-Dimethylpyrazine (2,5-DMP) and tetramethylpyrazine (TTMP) were produced using Bacillus subtilis IFO 3013 grown on soybeans. Solid-state cultivations were carried out either in 100-ml bottles or in a fixed-bed column reactor, both systems being at 27 °C. Optimization studies showed that the best way to produce the two above aroma compounds involved two separate processes. 2,5-DMP was obtained using soybeans enriched with 75 g threonine/kg initial dry weight (i.d.w.), giving 0.85 g metabolite/kg i.d.w. after 6 days. TTMP production involved addition of 90 g/kg i.d.w. acetoin to soybeans, and 2.5 g/kg i.d.w. was recovered after 14 days. These results demonstrated the suitability of solid-state cultivation for production of high-added-value compounds.

Biomass estimation in solid state fermentation

Abstract: During a solid state fermentation process, the microorganisms are intimately bound to a solid matrix, which poses difficulties for biomass measurements. Unlike submerged fermentation, fungal biomass cannot be quantitatively separated from the solid medium, and hence, direct measurements are impossible.

Solid State Fermentation of Lignocellulosic Waste for Cellulase and β-Glucosidase Production by Cocultivation ofAspergillus ellipticusand Aspergillus fumigatus

Abstract: Lignocellulosic wastes available in abundance can be excellent substrates for the production of cellulase and β-glucosidase enzymes by solid state fermentation (SSF). A cellulase system, showing enhanced hydrolytic potential and β-glucosidase under SSF, was obtained by cocultivation of Aspergillus ellipticus and Aspergillus fumigatus. Different types of substrates and various pretreatments were used to improve hydrolytic process. Among the various substrates examined, sugarcane bagasse gave the highest activity and 2% calcium hydroxide treatment was found to be the most favorable treatment for the enzyme production. The maximum enzyme production was obtained on the eighth day of the fermentation process.

Coconut cake – a potent substrate for the production of lipase by Candida rugosa in solid-state fermentation

Abstract: Investigations were conducted with the aim of producing extracellular lipase from Candida rugosa by solid-state fermentation (SSF), using coconut oil cake (COC) as a solid substrate. To optimize production, various modifications were made to enrich the substrate by supplementing it with mineral solution, different carbon sources and several inorganic as well as organic nitrogen sources. Among them, urea (1%), peptone (3%) and maltose (5%) were found to be most suitable. Addition of olive oil (10%) encouraged lipase synthesis. The maximum lipase activity in the enriched substrate was 87.76 units per gram of dry fermented substrate [U/gds] compared to 25.81 U/gds in the raw cake at 96 h of fermentation, and growth was as high as 14.44 mg/gds of glucosamine. This was reached at 72 h in the enriched substrate. C. rugosa growth was calculated indirectly by estimating the glucosamine content in the cell wall after its hydrolysis. The enzyme yield was far better than any values reported as yet.

Gibberellic acid production using different solid-state fermentation systems

Abstract: Gibberellic acid production in liquid fermentation was compared with production of this compound in solid-state fermentation systems using cassava flour, sugar cane bagasse and low density polyurethane. Gibberella fujikuroi produced 23 mg of gibberellin/ml in 120h of liquid fermentation. Solid-state fermentation on bagasse showed excellent growth but presented gibberellin extraction problems. Very low production and growth was observed in solid-state fermentation with low density polyurethane as an inert support. Solid-state fermentation on cassava flour showed high production (250 mg/kg of dry solid medium) in a very short time (36h).

Solubilisation and mineralisation of [14C]lignocellulose from wheat straw by Streptomyces cyaneus CECT 3335 during growth in solid-state fermentation

Abstract: Nine Streptomyces strains were screened for their ability to solubilise and mineralise 14C-labelled lignin during growth in solid-state fermentation. Streptomyces viridosporus was confirmed as an active lignin-degrading organism along with a new isolate, Streptomyces sp. UAH 15, further classified as Streptomyces cyaneus CECT 3335. This organism was able to solubilise and mineralise the [14C]lignin fraction of lignocellulose (44.96 ± 1.77% and 3.41 ± 0.48% respectively) after 21 days of incubation. Cell-free filtrates from Streptomyces sp. grown in solid-state fermentation were capable of solubilising up to 20% of the [14C]lignin after 2 days incubation, with most of the product detected in the acid-soluble rather than in the water-soluble fraction. Identification of the extracellular enzymes produced during growth of S. cyaneus CECT 3335 revealed that extracellular peroxidase and phenol oxidase activities were present, with the activity of phenol oxidase being 100 times greater than peroxidase activity. The activity of these two enzymes was found to correlate with both solubilisation and mineralisation rates. This is the first report of phenol oxidase activity produced by a Streptomyces strain during growth in solid-state fermentation. A role for the enzyme in the solubilisation and mineralisation of lignocellulose by S. cyaneus is suggested.

Special transformation processes using fungal spores and immobilized cells.

Abstract: Although many microbial processes have been described which are able to produce interesting aroma compounds, the number of industrial applications are limited. Reasons for this are in most cases low final product yield, low biotransformation rates, substrates and/or end-products inhibition, toxicity towards the microorganisms themselves and difficulties of recovery from the bioreaction mixture. This means that the development of specific catalysts and processes is an important challenge for researchers in this field. This review presents two special kinds of catalysts, fungal spores and immobilized cells, with emphasis on their production and on their use in the production of aroma compounds. The production of fungal spores by solid state fermentation is described in greater detail. In the second part, this review also offers examples of development of three production processes, the production of methyl ketones of spores of Penicillium roquefortii, the hydroxylation of β-ionone by immobilized Aspergillus niger cells, and the production of alkyl pyrazines by bacterial in liquid and solid media. For each of these processes, the analysis of limiting steps—biological and/or physico-chemical—is presented and the significant role of process conditions to increase aroma yield is discussed.

Production of β-galactosidase from thermophilic fungus Rhizomucor sp

Abstract: A thermostable β-galactosidase was produced extracellularly by a thermophilic Rhizomucor sp, with maximum enzyme activity (0.21 U mg−1) after 4 days under submerged fermentation condition (SmF). Solid state fermentation (SSF) resulted in a nine-fold increase in enzyme activity (2.04 U mg−1). The temperature range for production of the enzyme was 38–55°C with maximum activity at 45°C. The optimum pH and temperature for the partially purified enzyme was 4.5 and 60°C, respectively. The enzyme retained its original activity on incubation at 60°C up to 1 h. Divalent cations like Co2+, Mn2+, Fe2+ and Zn2+ had strong inhibitory effects on the enzyme activity. The K m and V max for p-nitrophenyl-β- D-galactopyranoside and o-nitrophenyl-β - D-galactopyranoside were 0.39 mM, 0.785 mM and 232.1 mmol min−1 mg−1 respectively. The K m and V max for the natural substrate lactose were 66.66 μM and 0.20 μ mol min−1 mg−1.

Solid state fermentation: Definition, Characteristics, Limitations and Monitoring

Abstract: SSF has important advantages and drawbacks due to its physico chemical features, namely, relatively low water activity and formation of significant gradients of temperature, nutrients and products SSF is also qualitatively different from the conventional submerged fermentation (SmF) process in relation to sporulation and production of enzymes as well as secondary metabolites Biomass estimation by respirometry and physical measurements such as infrared spectroscopy, pressure drop measurements and image analysis are being for different culture systems

Solid state fermentation of rice chaff for fibrinolytic enzyme production by Fusarium oxysporum

Abstract: Rice chaff was used as the substrate for the production of fibrinolytic enzyme by Fusarium oxysporum in solid state fermentation. The optimized moisture content of the medium was 30 - 50% (v/w). An inoculum of 5 - 10% (v/v) and an average particle size of 400 μm for the substrate were optimum for productivity and enzyme activity of 80 IU per ml filtrate was achieved after 96 hours of fermentation.

Production of Cyclosporin A by solid state fermentation

Abstract: The production of Cyclosporin A using wheat bran as the solid substrate was attempted using Tolypocladium sp and it was found that the yield was 10 times more than the yield obtained by submerged fermentation Hydrolysing the wheat bran using dilute HCl was found to increase the yield Different solvents were used for the optimization of extraction of Cyc A from the fermented bran

Production of the mycelium of shiitake (Lentinus edodes) mushroom and investigation of its bioactive compounds

Abstract: Mushroom cultivation embodies the principles of microbiology, environmental technology, and solid state fermentation in the conversion of domestic, agricultural and industrial organic waste materials into food for humans. Because of the large demand for edible mushrooms as a food and as a flavouring agent, there is research interest in attempting to produce flavour-rich mushroom mycelium in submerged fermentation. In addition to its use as food, Lentinus edodes (Shiitake) has been reported to have a number of beneficial health and medical effects. The aim of this work was to find an economical method to produce Shiitake mycelium in submerged culture, and then to study whether the bioactive compound (eritadenine) and the flavour components (the main component lenthionine) were produced by Lentinus mycelium. Lentinus edodes mycelium was successfully produced in submerged culture (biomass productivity was 1.0-1.2%) and a considerable reduction could be achieved in the time required for mushroom production as compared to the traditional technologies. On the basis of the GC-MS measurements it was proved that eritadenine, the bioactive compound was produced in the Shiitake mycelium. Based on NBS library data lenthionine, trithiolane and other aroma compounds were successfully identified in the biomass and in the fruiting body as well.

Chemical characterization and spectroscopic analysis of the solubilization products from wheat straw produced by Streptomyces strains grown in solid-state fermentation.

Abstract: The effects of two extraction procedures on the yield and properties of APPL (acid-precipitable polymeric lignin, or solubilized lignocellulose) produced by four streptomycetes during growth in solid-state fermentation were examined. When APPL was extracted with NaOH (0.1 M) rather than distilled water, yields increased threefold, with Streptomyces chattanoogensis exhibiting maximum solubilization levels [163 mg product (g straw)-1]. Alterations in the characteristics of APPL obtained during extraction with NaOH were detected using cross-polarization and magic-angle spinning (CPMAS) 13C NMR and IR spectroscopy and by GC-MS analysis after CuO oxidation, with the most significant changes detected in the cinnamic acid and lignin moieties. When APPL was extracted with NaOH, ester links between hemicellulose and lignin and between hemicellulose and cinnamic acid were cleaved, resulting in a decrease in the alkyl and carbonyl groups attached to lignin, enabling greater solubilization. Yields of APPL extracted with water were lower, but spectral characterization of this APPL suggested a possible role for actinomycete peroxidases and phenolic acid esterases in lignin solubilization. For industrial solubilization of lignocellulose, a possible role for the application of streptomycetes, or their enzymes, in alkali extraction is suggested as a means of increasing solubilization levels.

An unstructured mathematical model for growth of Pleurotus ostreatus on lignocellulosic material in solid-state fermentation systems

Abstract: Inedible plant material, generated in a Controlled Ecological Life Support System (CELSS), should be recycled preferably by bioregenerative methods that utilize enzymes or micro-organisms. This material consists of hemicellulose, cellulose, and lignin with the lignin fraction representing a recalcitrant component that is not readily treated by enzymatic methods. Consequently, the white-rot fungus,Pleurotus ostreatus, is attractive since it effectively degrades lignin and produces edible mushrooms. This work describes an unstructured model for the growth ofP. ostreatus in a solid-state fermentation system using lignocellulosic plant materials fromBrassica napus (rapeseed) as a substrate at three different particle sizes. A logistic function model based on area was found to fit the surface growth of the mycelium on the solid substrate with respect to time, whereas a model based on diameter, alone, did not fit the data as well. The difference between the two measures of growth was also evident for mycelial growth in a bioreactor designed to facilitate a slow flowrate of air through the 1.5 cm thick mat of lignocellulosic biomass particles. The result is consistent with the concept of competition of the mycelium for the substrate that surrounds it, rather than just substrate that is immediately available to single cells. This approach provides a quantitative measure ofP. ostreatus growth on lignocellulosic biomass in a solid-state fermentation system. The experimental data show that the best growth is obtained for the largest particles (1 cm) of the lignocellulosic substrate.

Production of cellulolytic enzymes by coculturing ofAspergillus ellipticus andAspergillus fumigatus grown on bagasse under solid state fermentation

Abstract: Production of cellulolytic enzymes on bagasse under solid state fermentation by coculture ofAspergillus ellipticus andAspergillus fumigatus was studied. Cocultivation ofA. ellipticus andA. fumigatus showed improved hydrolytic and Β-glucosidase activities as compared to the occasions when they were used separately. Various pretreatment methods were used to make cellulose accessible to enzymatic attack. Best results were obtained through pretreatment with 2% (w/v) calcium hydroxide. Maximum enzyme production was obtained after 8 d of fermentation process.

Citric acid production on three cellulosic supports in solid state fermentation

Abstract: Six strains of Aspergillus niger were screened in liquid medium and strain LPB 21 was selected for further studies on three different agro-industrial wastes/residues for production of citric acid by solid state fermentation. Cassava bagasse was found to be a better substrate than vegetable sponge and sugar cane bagasse. Citric acid production and yields were 13.64 g/100 g dried substrate and 41.78 %, respectively with the use of cassava bagasse. Studies on optimization of parameters for production of citric acid by A. niger LPB 21 in cassava bagasse medium indicated that 50% of initial moisture content, initial pH of 2.0, aeration rate of 60 ml/min/column and 26°C fermentation temperature are the optimum values. Under these optimized conditions, the production of citric acid was 280 g/kg dry substrate at 120 hours, which corresponds to the yield of 70% based on sugars consumed. Data on kinetics of pH changes, moisture level, loss of weight of the substrate, starch utilization and alpha-amylase production give insights in the process.

Lignin-degrading enzymes produced by Pleurotus species during solid state fermentation of wheat straw

Abstract: Three enzymes, i.e. manganese peroxidase (MnP), aryl-alcohol oxidase (AAO) and laccase, presumptively involved in lignin degradation, were detected and quantified during the solid state fermentation (SSF) of wheat straw with five Pleurotus species. The highest levels were produced by P. pulmonarius. In the course of the study, it was realized that several aspects of the physiology of ligninolysis during SSF differed from those reported in liquid culture. In particular, MnP activity appeared during a more extended period of time, and it was not dependent on the presence of peptone in the medium or inhibited by Mn2+, as in liquid cultures of Pleurotus species. It is suggested that these differences are the consequence of the artificial growth conditions prevailing in liquid cultures of basidiomycetes. In particular, the separation between growth phase and secondary metabolism can be observed only in liquid culture. Under SSF conditions, a third type of metabolism probably occurs, characterized by close relationships between hyphal growth and secondary metabolism events, including production and release of ligninolytic enzymes for enabling substrate colonization. Finally, the use of 14C-lignin straw provide indirect evidence for MnP involvement in lignin degradation under SSF conditions (probably via Mn3+ formation), since the addition of Mn2+, which did not increase MnP levels, strongly stimulated lignin mineralization by P. pulmonarius.

Coconut like aroma production by Trichoderma harzianum in solid state fermentation

Abstract: From the present work, it is now established that, by solid state fermentation (SSF), it is possible to produce 6-pentyl-α-pyrone (6-PP), an unsaturated δ-lactone with a strong odour of coconut, by using Trichoderma harzianum. 6-PP has been produced on a solid substrate, impregnated with a culture medium of a very high carbon/nitrogen (C/N) ratio, after an initial biomass production stage in a liquid culture medium at a low C/N ratio. 6-PP is the main component. Other volatile compounds accompanied this biosynthesis, and became more diversified with the progress of fermentation. The amount of 6-PP produced during SSF, following a 5 day culture, was 2.8±0.5 mg/g dry matter. Therefore, the 6-PP concentration produced during SSF is greater than that reported in literature during liquid culture. 6-PP does not inhibit growth during SSF. Moreover, with a nitrogen deficiency, the strain sporulated on a solid substrate. Semi-continuous 6-PP production by medium inoculation may, therefore, be possible.

Effect of elevated temperature on Trichoderma viride SL-1 in solid state fermentations

Abstract: Cellulase productions in solid state fermentation (SSF) by Trichoderma viride SL-1 were conducted in a column. Periodically oscillating the temperature in the range of 30-50iC in symmetrical or asymmetrical modes had no adverse effect on productivity. Effective activation of spore germination was found when the spores were treated twice at 30iC for 30 min. The results are useful in the performances of SSF processes.

Prospect for production of Pleurotus sajor - caju from cassava fibrous waste

Abstract: Cassava fibrous waste, alone or in combination with sugar cane bagasse, was studied for its potential for production of Pleurotus sajor-caju LPB 19 in solid state fermentation. Various physico-chemical parameters such as fermentation temperature, initial pH of the medium, enrichment of the medium with glucose and the level of NaC1 in the medium were studied, along with production of fruit bodies. The data indicated high potential of cassava fibrous waste in the production of Pleurotus mushroom, as the average production of fresh fruit bodies and the biological efficiency of the process involving 80: 20 ratio of cassava bagasses: sugar cane bagasse medium are excellent. The work provides a novel approach for upgradation of cassava fibrous waste.

Solid state fermentation of lignocellulosics into animal feed with white rot fungi

Abstract: The high content of polysaccharides in lignocellulosics, particularly cereal straws, is a potential source of dietary energy for ruminants. However, their nutritive value is limited because of the poor digestion of complex polysaccharide in the rumen. In order to increase the digestibility of lignocellulose, biological methods of delignification can be used. The principle of these methods is the splitting of the cellulose-lignin complex by extraction or decomposition of lignin. The main problem of biological upgrading of lignocelluloses into feed is to find suitable micro-organisms, with metabolic patterns different from those of the rumen flora and fauna and a cheap large scale process. Ideal micro-organisms for upgrading of lignocellulosics into animal feed should have a strong lignin metabolism, with a low degradation of cellulose and hemicellulose. In this review, principles of solid state fermentation and fungal activities on lignocelluloses are briefly summarized.