Showing papers on "Solid-state fermentation published in 2019"

Construction of Synthetic Microbiota for Reproducible Flavor Compound Metabolism in Chinese Light-Aroma-Type Liquor Produced by Solid-State Fermentation

Abstract: Natural microbiota plays an essential role in flavor compounds used in traditional food fermentation; however, the fluctuation in natural microbiota results in inconsistency in food quality. Thus, it is critical to reveal the core microbiota for flavor compound production and to construct a synthetic core microbiota for use in constant food fermentation. Here, we reveal the core microbiota based on their flavor production and cooccurrence performance, using Chinese light-aroma-type liquor as a model system. Five genera, Lactobacillus, Saccharomyces, Pichia, Geotrichum, and Candida, were identified to be the core microbiota. The synthetic core microbiota of these five genera presented a reproducible dynamic profile similar to that in the natural microbiota. A Monte Carlo test showed that the effects of five environmental factors (lactic acid, ethanol, and acetic acid contents, moisture, and pH) on the synthetic microbiota distribution were highly significant (P 0) with that in the natural liquor fermentation process, and the flavor profile presented a similar composition. It indicated that the synthetic core microbiota is efficient for reproducible flavor metabolism. This work established a method for identifying core microbiota and constructing a synthetic microbiota for reproducible flavor compounds. This work is of great significance for the tractable and constant production of various fermented foods. IMPORTANCE The transformation from natural fermentation to synthetic fermentation is essential in constructing a constant food fermentation process, which is the premise for stably making high-quality food. According to flavor-producing and cooccurring functions in dominant microbes, we provided a system-level approach to identify the core microbiota in Chinese light-aroma-type liquor fermentation. In addition, we successfully constructed a synthetic core microbiota to simulate the microbial community succession and flavor compound production in the in vitro system. The constructed synthetic core microbiota could not only facilitate a mechanistic understanding of the structure and function of the microbiota but also be beneficial for constructing a tractable and reproducible food fermentation process.

Fungal Laccase Production from Lignocellulosic Agricultural Wastes by Solid-State Fermentation: A Review.

Abstract: Laccases are copper-containing oxidase enzymes found in many fungi. They have received increasing research attention because of their broad substrate specificity and applicability in industrial processes, such as pulp delignification, textile bleaching, phenolic removal, and biosensors. In comparison with traditional submerged fermentation (SF), solid-state fermentation (SSF) is a simpler technique for laccase production and has many advantages, including higher productivity, efficiency, and enzyme stability as well as reduced production costs and environmental pollution. Here, we review recent advances in laccase production technology, with focus on the following areas: (i) Characteristics and advantages of lignocellulosic agricultural wastes used as SSF substrates of laccase production, including detailed suggestions for the selection of lignocellulosic agricultural wastes; (ii) Comparison of fungal laccase production from lignocellulosic substrates by either SSF or SF; (iii) Fungal performance and strain screening in laccase production from lignocellulosic agricultural wastes by SSF; (iv) Applications of laccase production under SSF; and (v) Suggestions and avenues for future studies of laccase production by fungal SSF with lignocellulosic materials and its applications.

Solid-State Yeast Fermented Wheat and Oat Bran as A Route for Delivery of Antioxidants.

Abstract: The purpose of our study was to evaluate the potential of solid-state yeast fermentation (SSYF) in improving the phenolic acid content and composition, and the antioxidant activity of commercial wheat bran (WB) and oat bran (OB). The ultrasound-assisted methanolic extracts were compared for their total phenolic content (TPC), phenolics composition, and in vitro antioxidant activity in order to study the effect of fermentation time on the chemical profile and activity of bioactive compounds. The comparative analysis revealed significant differences (p < 0.05) between days of fermentation (0 through 6). The highest TPCs were obtained on day 3 for WB (0.84 ± 0.05 mg of gallic acid equivalents [GAE]/g dry weight [DW]), and on day 4 for OB (0.45 ± 0.02 mg GAE/g DW). The highest relative percentage increase in the phenolics concentration of WB was also registered on day 3 (ferulic acid +56.6%, vanillic acid +259.3%, dihydroxybenzoic acids +161.2%, apigenin-glucoside +15.3%); for OB, this was observed on day 4 (avenanthramide 2f +48.5%, ferulic acid +21.2%). Enhanced antioxidant activities were significantly correlated with the highest TPCs. Our results suggest that SSYF may be a useful procedure for enrichment of antioxidants in cereal bran, considering the design of different functional foods and nutraceuticals.

Production and optimization of lipase using Aspergillus niger MTCC 872 by solid-state fermentation

Abstract: Lipases are serine hydrolases that degrade triglycerides, an attribute that treasures wide applications in biodiesel production, detergent, chemical industries, etc. The most sought after the application is in the high quality and economical production of biodiesel under mild reaction conditions and simplified product separation. For the said application, fungal lipases are ideal catalysts that could effectively catalyze esterification and transesterification reactions with their specific ability to release fatty acids from 1, 3 positions of acylglycerols. In the present work, to facilitate bulk synthesis, lipase production using Aspergillus niger MTCC 872 was studied by solid-state fermentation (SSF). The chosen fungal strain was evaluated for lipase production using a mixture of agro-industrial substrates viz. rice husk, cottonseed cake, and red gram husk in various combinations at flask level. Tri-substrate mixture (rice husk, cottonseed cake, and red gram husk) combined in the ratio of 2:1:1 has shown the maximum lipase activity 28.19 U/gds at optimum cultivation conditions of temperature 40 °C, moisture content 75% (v/w), pH 6.0 and initial spore concentration of 5.4 million spores per mL. Further studies were performed for scale-up of lipase from flask level to lab scale using tray fermenter. Lipase activity was found to be 24.38 U/gds and 21.62 U/gds for 100 g and 1000 g substrate respectively. This is the first report on the production of lipase from Aspergillus niger MTCC 872 using tri-substrate mixture of rice husk (RH), cottonseed cake (CSC), and red gram husk (RGH). Moreover, comparison between individual, binary, and tri-substrate mixture was carried out for which the highest lipase activity was observed for tri-substrate mixture. In addition, comparable results were found when scale-up was performed using tray fermenter. Thus, the current work signifies usage of agro-industrial residues as substrates for enzyme production by solid-state fermentation process as an effective alternative to submerged fermentation for industrial applications.

Optimization of Protease and Amylase Production by Rhizopus oryzae Cultivated on Bread Waste Using Solid-State Fermentation

Abstract: This research was carried for the coproduction of two industrial enzymes: α-amylase and protease via SSF by Rhizopus oryzae on humidified bread waste. Fermentation time, inoculum size, initial moisture content, salt solutions, and the thickness of the substrate were investigated one by one. Fungus culture was carried out in sterile aluminum trays, and pH was adjusted to 5.5. The main results showed that the highest levels of enzyme production were obtained at 120 h, 65% relative humidity, height media of 1 cm, 105 spore/g, and M-9 solution (g/L): NaH2PO4, 12.8; KH2PO4, 3; NaCl, 0.5; NH4Cl, 1; MgSO4 7H2O, 0.5; CaCl2 2H2O, 0.01. α-Amylase (100 U/g) and protease (2400 U/g) produced by SSF from Rhizopus oryzae (CH4) on BW as substrate are of great interest in industries and could be valorized as enhancers of the bread making process.

Production of cellulases by solid state fermentation using natural and pretreated sugarcane bagasse with different fungi

Abstract: Lignocellulosic biomass is an important source of energy and it has been extensively studied in the production of second generation ethanol. For this purpose, the complex lignocellulosic matrix must be deconstructed by thermal or chemical pretreatment, followed by cellulose depolymerization using cellulolytic enzymes to release simple fermentable sugars. This process still has several techno-economical drawbacks, such as the cost of enzymes. Aiming to reduce the cost of theses enzymes, their production have been studied by solid-state fermentation (SSF) using low-cost agroindustrial residues as carbon source to the microbial growth. In this context, this work aimed at studying the operational conditions (temperature and moisture content) for the production of cellulases from the fungi Penicillium sp., Rhizomucor sp. and Trichoderma koningii INCQS 40331 (CFAM 422), utilizing natural sugarcane bagasse (NSB) and pretreated by acid-alkaline solution (AAB) and hydrogen peroxide (HPB) as substrates. The study was performed by using three-level factorial design (32) with central points. The results showed that the more suitable fungus for cellulases production was the Trichoderma koningii (8.2 IU/g substrate), followed by Penicillum sp (1.7 IU/g substrate). Moreover, the best results were obtained using NSB for all fungi. Statistical analyses showed that the temperature has a greater effect on the production of cellulases by the evaluated fungi.

Solid-state fermentation with Aspergillus niger to enhance the phenolic contents and antioxidative activity of Mexican mango seed: A promising source of natural antioxidants

Abstract: This study examines changes in phenolic compounds and the antioxidant activity of Mexican mango seed in the bioprocess of solid-state fermentation (SSF) with the fungus Aspergillus niger GH1. The chemical composition and evaluation of mango seed as solid fermentation substrate support was also evaluated. Because of the chemical composition and the rapid growth of the fungus, mango seed is a suitable material to be used in SSF. The results showed that SSF of mango seed mobilized the polyphenolic compounds and improved the nutraceutical properties. The total phenol content in ethanol extract increased (p

Solid State Fermentation of Brewers’ Spent Grains for Improved Nutritional Profile Using Bacillus subtilis WX-17

Abstract: Brewers’ spent grains (BSG) are underutilized food waste materials produced in large quantities from the brewing industry. In this study, solid state fermentation of BSG using Bacillus subtilis WX-17 was carried out to improve the nutritional value of BSG. Fermenting BSG with the strain WX-17, isolated from commercial natto, significantly enhanced the nutritional content in BSG compared to unfermented BSG, as determined by the marked difference in the level of metabolites. In total, 35 metabolites showed significant difference, which could be categorized into amino acids, fatty acids, carbohydrates, and tricarboxylic acid cycle intermediates. Pathway analysis revealed that glycolysis was upregulated, as indicated by the drop in the level of carbohydrate compounds. This shifted the metabolic flux particularly towards the amino acid pathway, leading to a 2-fold increase in the total amount of amino acid from 0.859 ± 0.05 to 1.894 ± 0.1 mg per g of BSG after fermentation. Also, the total amount of unsaturated fatty acid increased by 1.7 times and the total antioxidant quantity remarkably increased by 5.8 times after fermentation. This study demonstrates that novel fermentation processes can value-add food by-products, and valorized food waste could potentially be used for food-related applications. In addition, the study revealed the metabolic changes and mechanisms behind the microbial solid state fermentation of BSG.

Production of value-added product from pineapple peels using solid state fermentation

Abstract: Pineapple (Ananas comosus) peels are agricultural plant residues that contribute to waste disposal problem and there is little information on their conversion to useful products. Solid state fermentation (SSF) of pineapple peels (with and without ammonium sulphate) was done with a view to increase their protein content using Trichoderma viride ATCC 36316 for 96 h at 30 °C. The study was carried out using conical flasks and on-farm solid state fermenter. Chemical composition (fat, crude and true proteins, carbohydrate and ash) of the unfermented and fermented peels were determined using standard methods. Unfermented pineapple peel had low values of 4.5, 2.84, 0.6, 6.8% for crude protein, true protein, fat and ash contents, respectively. The SSF using T. viride with or without the addition of (NH4)2SO4 increased the chemical compositions of the pineapple peels. Higher protein yields were recorded when (NH4)2SO4 was used as nitrogen source. T. viride and (NH4)2SO4 increased the crude protein content from 4.5 to 14.9% when fermentation was done using conical flask. With on-farm scale fermenter, protein yields increased further. SSF of pineapple peels with T. viride produced high protein fungal biomass and may be recommended as suitable for animal feed.

A metabolomic approach to understand the solid-state fermentation of okara using Bacillus subtilis WX-17 for enhanced nutritional profile.

Abstract: Okara is a major agro-waste produced from the soybean industry. To hydrolyze the okara and enable nutrient release, a strategy to valorize okara using solid-state fermentation with food grade Bacillus subtilis (B. subtilis) WX-17 was carried out. The study showed that fermentation of okara with B. subtilis WX-17 improved its overall nutritional content. The total amino acids content increased from 3.04 ± 0.14 mg/g in unfermented okara to 5.41 ± 1.21 mg/g in okara fermented with B. subtilis WX-17. Total fatty acids content increased from 153.04 ± 5.10 to 166.78 ± 2.41 mg/g okara, after fermentation. Antioxidant content (DPPH) also increased by 6.4 times after fermentation. To gain insight into the mechanism, gas chromatography–mass spectrometry analysis was carried out. In total, 49 metabolites were detected, which could be classified mainly into carbohydrates, TCA cycle metabolites, amino acids and fatty acids. The decrease in carbohydrate metabolites, showed that glycolysis was upregulated. This would have provided the energy and metabolic flux towards the amino acid and fatty acid pathway. This is also in line with the increased amino acids and fatty acid production seen in okara fermented with B. subtilis WX-17. The findings of this work demonstrated the potential of using B. subtilis WX-17 fermentation, to enhance the nutritional profile of okara. This could serve as a potential low-cost animal feed or incorporated into the human diet.

Pectinase Production from Schizophyllum commune Through Central Composite Design Using Citrus Waste and Its Immobilization for Industrial Exploitation

Abstract: Pectinase is an important group of industrial enzymes. Pectinase manufacturing occupies about 10% of the overall enzyme production world over. The aim of this study is to produce pectin lyase from Schizophyllum commune using the mosambi (sweet lime) fruit peels as substrate in solid state fermentation. The cultural parameters optimized through response surface methodology showed maximum pectin lyase production of 480.45 U/mL at initial medium pH of 6, incubation temperature of 35 °C, time period of 1 day, substrate concentration of 15 g and 3 mL of inoculum size. A purification fold of 3.08 with 355 U/mg specific activity and 4.16% yield was obtained after purification. Enzyme immobilization was done by entrapment with sodium alginate and adsorption with chitosan. Chitosan immobilized enzyme exhibited best thermal stability in the range of 45–55 °C and pH 8.0–9.0. Enzyme activity was stimulated in the presence of Ca2+ and Mg2+ while EDTA inhibited the enzyme activity. Chitosan immobilized pectin lyase was stable up to six cycles of reuse. The pH and thermal stability of S. commune pectin lyase makes it an important enzyme for industrial use. The results showed that pectin lyase produced from S. commune has significant potential for applications in the detergent and fruit juice industry. The enzyme produced from citrus agro waste via the proposed optimized biotechnological process can be explored for multiple industrial applications.

Soybean residue (okara) fermentation with the yeast Kluyveromyces marxianus

Abstract: The soybean residue (okara) with high moisture content has generally been discarded, which has led to economic loss and socio-environmental problems. The effects of solid state fermentation using Kluyveromyces marxianus on the nutritional components, beany odor and processing properties of soybean residue were studied. The results showed that K. marxianus fermented soybean residue (FSR) had an increase in crude fat (24.5%), soluble dietary fibers (158%) and polysaccharides (262%), while phytic acid (61.7%) and the activity of a trypsin inhibitor (92.7%) decreased. A significant reduction in the beany odor was also observed. FSR showed higher water absorption and better emulsifying properties. Overall, the study indicated that fermentation with K. marxianus resulted in improved nutritional values and processing characteristics of the soybean residue.

Use of wastes for sophorolipids production as a transition to circular economy: state of the art and perspectives

Abstract: Chemical processes and petroleum-based chemicals are being substituted by biological processes and bioproducts. Surfactants and biosurfactants are an example of this trend. Among the biosurfactants, sophorolipids (SLs) have excellent surface and interfacial tension properties, which make them ideal to be used in a wide variety of applications. SLs are produced at full scale through submerged fermentation of pure substrates (glucose and oleic acid). However, research trends suggest that there is a lot of interest to produce SLs from waste effluents and other low-cost substrates, both in submerged and solid-state fermentation processes. This study reviews the current research in the production of SLs via fermentation processes, focusing on those using wastes, by-products, or low-cost substrates (liquids or solids). It details the substrates, process variables, microorganisms, and use of supplementary media for batch, fed-batch, and continuous submerged or solid-state fermentation processes. Sophorolipids production based on industrial by-products and waste effluents presents huge potential for its application at an industrial scale in a more economical and environmentally friendly process, boosting the necessary change to circular economy.