Showing papers on "Solid-state fermentation published in 2017"

Unraveling Core Functional Microbiota in Traditional Solid-State Fermentation by High-Throughput Amplicons and Metatranscriptomics Sequencing

Abstract: Fermentation microbiota is specific microorganisms that generate different types of metabolites in many productions. In traditional solid-state fermentation, the structural and functional changes in core microbiota influence the quality and quantity of products. As typical food fermentation, Chinese Maoti-flavor liquor production has the particular mechanism with complex microorganisms and wide variety of metabolites. However, it remains unclear that species succession and function shift of core microbiota in this traditional food fermentation. Here, high-throughput amplicons (16S rRNA gene amplicons sequencing and internal transcribed space amplicons sequencing) and metatranscriptomics sequencing technologies are combined to reveal the structure and function of core microbiota in Chinese Maoti-flavor liquor production. In addition, ultra-performance liquid chromatography and headspace-solid phase microextraction-gas chromatography-mass spectrometer are employed to quality and qualitative analysis the major flavor metabolities. Amplicons analysis indicates species distribution of core micorbiota includes 10 fungal and 11 bacterial genera. Besides, metatranscriptomic analysis indicates pyruvate metabolism in yeasts (genera Pichia, Schizosaccharomyces, Saccharomyces and Zygosaccharomyces) and lactic acid bacteria (genus Lactobacillus) reflects different stages in production of flavor components. Overall, these findings have shown that there are two stages in production. Stage I is high-level alcohol (ethanol) production period that genus Schizosaccharomyces serves as the core functional microorganism. Stage II is high-level acid (lactic acid and acetic acid) production period that genus Lactobacillus serves as the core functional microorganism. Furthermore, functional shift from genus Schizosaccharomyces to genus Lactobacillus drives flavor components conversion from alcohol (ethanol) to acid (lactic acid and acetic acid) in Chinese Maotai-flavor liquor production. This study provides new attempts to understand the effects of core functional microbiota in Chinese Maotao-flavor liquor production and explore the fermentation microbiota under different environmental conditions further.

Microbial Enzymes of Use in Industry

Abstract: A large variety of microorganisms produce potent biocatalysts as enzymes which vary in their microbial sources, chemical properties, and mechanisms. Usually, microbial enzymes catalyze the reactions of hydrolysis, oxidation, or reduction. Microbial enzymes have different active site motifs targeting diversified substrates. They may catalyze the reaction by completely different mechanisms even when they belong to the same class. Microbial enzymes are mainly produced by submerged fermentation and solid state fermentation. The enormous diversity of microbial enzymes makes them an interesting group of products for application in many areas such as agricultural, chemical industry, food processing industry, textile industry, pharmaceuticals, wood processing industry, analytical applications, cosmetics, and environmental pollution control, such as bioremediation and biodegradation. In this chapter, classification and microbial resources, microbial production, and industrial applications of a group of industrially used microbial enzymes, such as carbohydrases, proteases and lipases, are described.

Solid-state fermentation of corn-soybean meal mixed feed with Bacillus subtilis and Enterococcus faecium for degrading antinutritional factors and enhancing nutritional value

Abstract: Corn and soybean meal (SBM) are two of the most common feed ingredients used in pig feeds. However, a variety of antinutritional factors (ANFs) present in corn and SBM can interfere with the bioavailability of nutrients and have negative health effects on the pigs. In the present study, two-stage fermentation using Bacillus subtilis followed by Enterococcus faecium was carried out to degrade ANFs and improve the nutritional quality of corn and SBM mixed feed. Furthermore, the microbial composition and in vitro nutrient digestibility of inoculated mixed feed were determined and compared those of the uninoculated controls. During the fermentation process, B. subtilis and lactic acid bacteria (LAB) were the main dominant bacteria in the solid-state fermented inoculated feed, and fermentation produced a large amount of lactic acid (170 mmoL/kg), which resulted in a lower pH (5.0 vs. 6.4) than the fermented uninoculated feed. The amounts of soybean antigenic proteins (β-conglycinin and glycinin) in mixed feed were significantly decreased after first-stage fermentation with B. subtilis. Inoculated mixed feed following two-stage fermentation contained greater concentratioin of crude protein (CP), ash and total phosphorus (P) compared to uninoculated feed, whereas the concentrations of neutral detergent fiber (NDF), hemicellulose and phytate P in fermendted inoculated feed declined (P < 0.05) by 38%, 53%, and 46%, respectively. Notably, the content of trichloroacetic acid soluble protein (TCA-SP), particularly that of small peptides and free amino acids (AA), increased 6.5 fold following two-stage fermentation. There was no difference in the total AA content between fermented inoculated and uninoculated feed. However, aromatic AAs (Phe and Tyr) and Lys in inoculated feed increased, and some polar AAs, including Arg, Asp, and Glu, decreased compared with the uninoculated feed. In vitro dry matter and CP digestibility of inoculated feed improved (P < 0.05) compared with the uninoculated feed. Our results suggest that two-stage fermentation using B. subtilis followed by E. faecium is an effective approach to improve the quality of corn-soybean meal mixed feed.

Solid state fermentation (SSF): diversity of applications to valorize waste and biomass

Abstract: Solid state fermentation is currently used in a range of applications including classical applications, such as enzyme or antibiotic production, recently developed products, such as bioactive compounds and organic acids, new trends regarding bioethanol and biodiesel as sources of alternative energy, and biosurfactant molecules with environmental purposes of valorising unexploited biomass. This work summarizes the diversity of applications of solid state fermentation to valorize biomass regarding alternative energy and environmental purposes. The success of applying solid state fermentation to a specific process is affected by the nature of specific microorganisms and substrates. An exhaustive number of microorganisms able to grow in a solid matrix are presented, including fungus such as Aspergillus or Penicillum for antibiotics, Rhizopus for bioactive compounds, Mortierella for biodiesel to bacteria, Bacillus for biosurfactant production, or yeast for bioethanol.

Design aspects of solid state fermentation as applied to microbial bioprocessing

Abstract: Solid state fermentation (SSF) refers to the microbial fermentation, which takes place in the absence or near absence of free water, thus being close to the natural environment to which the selected micro organisms, especially fungi, are naturally adapted. SSF has been used in the world for a long time. This technology is commonly known in the East, for traditional manufacture of fermented foods, and in the west, for mould-ripened cheese. It can be defined as a system, in which the growth of selected microorganism(s) occurs on solid materials with low moisture contents and has been identified as a potentially important methodology and technique in biotechnology. Nowadays, SSF is an economically viable, practically acceptable technology for large-scale bioconversion and biodegradation processes. Development of sustainable SSF and bioprocess technology is an emerging, multidisciplinary field with possible application to the production of enzymes, chemicals, bioethanol and pharmaceuticals. SSF offers many advantages over conventional submerged fermentation (SMF) such as, simple and inexpensive substrates, elimination of the need for solubilisation of nutrient from within solid substrates, elimination of the need for rigorous control of many parameters during fermentation, product yields are mostly higher, lower energy requirements, produce less waste water, no foam generation and relatively easy recovery of end products. SSF provides flexibility in terms of the raw materials to be used and their capability to produce various value-added products.

Production of ligninolytic enzymes by solid state fermentation using Pleurotus ostreatus

Abstract: Solid state fermentation (SSF) stands out in the production of lignocellulolytic and other industrially important enzymes SSF, an alternative culture method, has several advantages over the conventional submerged ones, like higher yields of enzymes The production of ligninolytic enzymes, such as laccase (Lac), manganese peroxidase (MnP), lignin peroxidase (LiP) and aryl alcohol oxidase (AAO) by Pleurotus ostreatus (Jacq) Pleurotus Kumm (MCC16) was investigated under SSF, which was performed using a support-substrate from potato peel waste (PPW) PPW as dry and fresh was pretreated with base to neutralize organic acids and distilled water Chemical content of PPW was investigated Ligninolytic enzyme production patterns were investigated during the growth of the organism for a period of 23 days at 25 °C in the stationary SSF using pretreated PPW The highest Lac and MnP activities were determined in dry PPW, pretreated with distilled water as 67083 ± 75 U/L and 25036 ± 50 U/L on day 17, respectively In addition, amylase and protease enzyme activities were detected under same conditions According to the results, PPW has a potential as supports for ligninolytic enzyme production by P ostreatus under SSF

Phenolic compounds, flavonoids, lipids and antioxidant potential of apricot (Prunus armeniaca L.) pomace fermented by two filamentous fungal strains in solid state system.

Abstract: The use of agricultural and food by-products is an economical solution to industrial biotechnology. The apricot press residues are abounding by-products from juice industry which can be used as substrates in solid state fermentation process (SSF), thus allowing a liberation and increase of content from various biomolecules with high added value. The evolutions of phenolic levels (by colorimetric assays and high performance liquid chromatography, HPLC–MS) and antioxidant activities (by DPPH assay) during SSF of apricot pomaces with Aspergillus niger and Rhizopus oligosporus were investigated. The changes in fatty acid compositions of oils in apricot kernels during SSFs were also analyzed by gas chromatography (GC–MS). The results showed that the levels of total phenolics increased by over 70% for SSF with R. oligosporus and by more than 30% for SSF with A. niger. A similar trend was observed in the amounts of total flavonoids (increases of 38, and 12% were recorded for SSF by R. oligosporus and A. niger, respectively). Free radical scavenging capacities of methanolic extracts were also significantly enhanced. The main phenolic compounds identified through HPLC–MS in fermented apricot press residues were chlorogenic acid, neochlorogenic acid, rutin, and quercetin 3-acetyl- glucoside. This work also demonstrated that the SSF with filamentous fungal strains not only helped in higher lipid recovery from apricot kernels, but also resulted in oils with better quality attributes (high linoleic acid content). The utilization of apricot by-products resulting from the juice industry as waste could provide an extra income and at the same time can help in solving solid waste management problems

Improvement of nutritional value and bioactivity of soybean meal by solid-state fermentation with Bacillus subtilis

Abstract: The main objective of this research was to evaluate the nutritional quality and bioactivity of soybean meal (SBM) by solid-state fermentation (SSF) with Bacillus subtilis. The results indicated that the contents of crude and soluble proteins, total phenol and flavonoid all increased distinctly, while trypsin inhibitor (TI) content decreased after fermentation. There was a slight difference in the total amino acids TAA profile between SBM and fermented soybean meal (FSBM), while the free amino acids (FAA) differed significantly. The result of high performance capillary electrophoresis analysis indicated that there were more soluble components in FSBM than that in SBM. Analysis of antioxidant activities showed that the reducing ability, scavenging DPPH and ABTS radical abilities of FSBM were all stronger than that of SBM. In addition, FSBM has been found having a strong inhibition on angiotensin I-converting enzyme (ACE) measured by HPLC revealing FSBM has antihypertensive activity. These results suggest that SSF with Bacillus subtilis can substantially improve both the nutritional quality and bioactivity of SBM.

New microbial resource: microbial diversity, function and dynamics in Chinese liquor starter

Abstract: Traditional Chinese liquor (Baijiu) solid state fermentation technology has lasted for several thousand years. The microbial communities that enrich in liquor starter are important for fermentation. However, the microbial communities are still under-characterized. In this study, 454 pyrosequencing technology was applied to comprehensively analyze the microbial diversity, function and dynamics of two most-consumed liquor starters (Jiang- and Nong-flavor) during production. In total, 315 and 83 bacterial genera and 72 and 47 fungal genera were identified in Jiang- and Nong-flavor liquor starter, respectively. The relatively high diversity was observed when the temperature increased to 70 and 62 °C for Jiang- and Nong-flavor liquor starter, respectively. Some thermophilic fungi have already been isolated. Microbial communities that might contribute to ethanol fermentation, saccharification and flavor development were identified and shown to be core communities in correlation-based network analysis. The predictively functional profile of bacterial communities showed significant difference in energy, carbohydrate and amino acid metabolism and the degradation of aromatic compounds between the two kinds of liquor starters. Here we report these liquor starters as a new functionally microbial resource, which can be used for discovering thermophilic and aerobic enzymes and for food and feed preservation.

Production, purification and biochemical characterization of an exo-polygalacturonase from Aspergillus niger MTCC 478 suitable for clarification of orange juice

Abstract: Polygalacturonases (PG) represent an important member of pectinases group of enzymes with immense industrial applications A fungal strain Aspergillus niger MTCC478 was used for the production of polygalacturonase both under submerged and solid-state fermentation condition Further its production was optimized under solid-state fermentation condition with media comprising of wheat bran and tea extract Purification of an exo-PG was achieved by acetone precipitation (60–90%) and CM-cellulose column chromatography revealing 1528-fold purification with a specific activity of 3347 U/mg protein and 12% yield A relative molecular mass of purified PG was approximately 1240 kDa The pH and temperature optimum was found to be 4 and 50 °C, respectively The k cat and K m value for degradation of PGA by the purified enzyme was found to be 194 s−1 and 23 mg/mL, respectively Cu2+ was found to enhance the PG activity while Ag+ completely inhibited the enzyme activity The application of the purified PG in orange juice clarification was elucidated

Changes in volatile profile of soybean residue (okara) upon solid‐state fermentation by yeasts

Abstract: Soybean residue (okara), a by-product of soymilk, is produced in large volumes by the soy food industry and is often discarded due to its undesirable flavour. As it contains a considerable amount of protein and fats, biotransformation of okara to improve its flavour presents an opportunity for alternative utilisation. This paper evaluated 10 yeasts in the solid-state fermentation of okara based on their volatile profiles as analysed with HS-SPME GC-MS/FID. Four ?dairy yeasts? (Geotrichum candidum, Yarrowia lipolytica, Debaryomyces hansenii and Kluyveromyces lactis) and six ?wine yeasts? (Saccharomyces cerevisiae, Lachancea thermotolerans, Metschnikowia pulcherrima, Pichia kluyveri, Torulaspora delbrueckii, and Williopsis saturnus) were studied. Results The main off-odourants in okara, hexanal and trans-2-hexenal, significantly decreased after fermentation due to their bioconversion into methyl ketones and/or esters. The okara fermented by dairy yeasts contained greater proportions of methyl ketones, while that by wine yeasts contained more ethyl and acetyl esters. Notably, the okara fermented by W. saturnus contained 13 esters and the total GC-FID peak area of esters was about 380 times that in fresh okara, leading to a perceptible fruity note. Conclusion Okara can be exploited as an inexpensive substrate for bioflavour extraction and/or a more pleasant food ingredient via yeast fermentation. ? 2016 Society of Chemical Industry

Laccase Production from Trametes versicolor in Solid-State Fermentation of Steam-Exploded Pretreated Cornstalk

Abstract: Laccase is an important enzyme used in removal of recalcitrant environmental wastes and industrial processes. The development of novel strategies for low-cost laccase production is needed to meet its demand. The solid-state fermentation (SSF) of steam-exploded corn stalk (SCS) significantly enhanced laccase production due that the steam explosion pretreatment disrupted the compact lignocellulosic structure, increased the surface area and soluble compounds accessible to biological utilization by Trametes versicolor. The pretreatment technique also released high level of the phenolic compounds which are putative inducers of laccase. As a result, laccase production from the SCS increased by more than 2.1-fold greater than that from the raw corn stalk. Together these results provide a powerful and low-cost strategy to enhance laccase production through the SSF of the renewable biomass.

Impact of Solid-State Fermentation (Aspergillus oryzae) on Functional Properties and Mineral Bioavailability of Black-Eyed Pea (Vigna unguiculata) Seed Flour

Abstract: Solid-state fermentation (SSF) represents a technological alternative feature for a great variety of legumes and cereals to improve their functional and nutritional properties. Iron and zinc deficiencies are major health concerns as a public health problem. Therefore, the present investigation was carried out to assess the consequences of SSF on functional properties and in vitro bioavailability of minerals through Caco-2 cells. Fungal strain Aspergillus oryzae (generally recognized as safe) was used for SSF. The effect of SSF on the functional properties (bulk density, water- and oil-binding capacities, emulsion activity and stability, and foaming capacity and stability) of a black-eyed pea flour sample was evaluated. SSF significantly (P < 0.05) decreased the bulk density of black-eyed pea flour; however, significant (P < 0.05) improvement was observed in other functional properties. An unfermented flour sample showed significantly (P < 0.05) decreased iron and zinc bioavailability and digestibility com...

Comparative assessment of effect of fermentation on phenolics, flavanoids and free radical scavenging activity of commonly used cereals

Abstract: The fermentation based enrichment of polyphenolics and antioxidants of commonly used cereals i.e. wheat, rice, oat, maize and sorghum was done using GRAS fungal strain A. oryzae . Significant (P O. sativa and T. aestivum followed by > S. bicolour > A. sativa > Z. mays which is mainly due to high enzyme activities as observed during their fermentation. A positive correlation was obtained between total phenol and flavanoid content with antioxidant activity. Role of α-amylase, xylanase and β-glucosidase enzymes in release of polyphenols and antioxidants during solid state fermentation of cereals was justified by a linear correlation obtained between total phenolic and flavanoid contents with enzyme activities.