Use In Fermentation Processes Research Articles

Extraction of fermentable sugars and phenolic compounds from Colombian cashew (Anacardium occidentale) nut shells using subcritical water technology: Response surface methodology and chemical profiling

Subcritical water extraction (SCWE) is a novel technology that uses water at high pressure and temperature to recover bioactive compounds. While promising, further studies are needed to fully understand the potential of SCWE when applied to cashew nut shells (CNS), which are rich in phenolic compounds, carbohydrates, and other natural substances. This study aimed to evaluate SCWE applied to CNS from Vichada, Colombia, using a surface response methodology and to perform a comprehensive chemical profiling of the recovered extracts and the remaining solids. A Box-Behnken experimental design was employed to study the extraction process, focusing on variables such as temperature, pressure, and solid-to-solvent ratio. The liquid extracts were analyzed using ultra-high-performance liquid chromatography and gas chromatography coupled with mass spectrometry, while the extracted solids were characterized using Fourier-transform infrared spectroscopy and scanning electron microscopy. The liquid extracts revealed a variety of compounds, including xylose, glucose, arabinose, long-chain phenols, organic acids, and furans. Extraction conditions significantly influenced the distribution of these compounds, with the optimal conditions for extracting fermentable sugars and organic acids identified as 180 °C, 15 bar, and a 20:1 mL/g solid-to-solvent ratio. The resulting hydrochar comprised lignin (58.82 ± 3.44 %) and structural carbohydrates (approximately 40 %), showing thermal stability up to 200 °C, OH functional groups on its surface, and a textured morphology under microscopy. These by-products have potential applications in various fields. This study demonstrates that SCWE effectively recovers valuable compounds from CNS for use in fermentation processes, suggesting that the resulting hydrochar could be utilized in soil amendment, adsorption, or energy applications. SCWE is highlighted as an innovative and environmentally friendly technology for managing cashew residual biomass, promoting sustainability and circularity in this production chain.

Use of fermentation processes for improving the dissolution of phosphorus and its recovery from waste activated sludge

ABSTRACT Recycling phosphorus from waste activated sludge has attracted a lot of interest to tackle the problem of phosphorus stocks depletion and the increase in food demand. In this study, the use of fermentation processes was investigated to enhance phosphorus dissolution from waste activated sludge to improve its recycling. Two fermentation processes, bioacidification and dark fermentation, were used on two different sludges fermented with wheat starch syrup in continuous operating conditions. Hydrogen yield from the co-substrate fermentation with waste activated sludge reached 3.9 mmolH2.gCODcosubstrate −1 yield during dark fermentation process and was negligible during bioacidification. Dissolved phosphorus in the waste activated sludge increased by 68% during bioacidification and by 43% during dark fermentation. In both processes, phosphorus dissolution was accompanied by iron, calcium and magnesium dissolution. Results show that fermentation enhances phosphorus dissolution in waste activated sludge to improve its recovery along with hydrogen and organic acids.

Stl1 transporter mediating the uptake of glycerol is not a weak point of Saccharomyces kudriavzevii's low osmotolerance

Saccharomyces kudriavzevii is a nonconventional and rather osmosensitive yeast with a high potential of use in fermentation processes. To elucidate the basis of its relative osmosensitivity, the role of the STL1 gene encoding a putative glycerol uptake system was studied. Under higher osmotic pressure, the addition of a low amount of glycerol to the growth medium improved the growth of S. kudriavzevii and the expression of the STL1 gene was highly induced. Deletion of this gene decreased the strain's ability to grow in the presence of higher concentrations of salts and other solutes. Moreover, the mutant had a disturbed homeostasis of intracellular pH. Expression of the SkSTL1 gene in Saccharomyces cerevisiae complemented the osmosensitivity of the S. cerevisiae hog1Δ stl1Δ mutant, and the gene's tagging with GFP localized its product to the plasma membrane. Altogether, a deficiency in glycerol uptake did not seem to be the reason for S. kudriavzevii's low osmotolerance; its Stl1 transporter properly contributes to the regulation of intracellular pH and is crucial to its survival of osmotic stress. SIGNIFICANCE AND IMPACT OF THE STUDY: An increasing demand for food products with benefits for human health turns the attention to less-exploited nonconventional yeasts with interesting traits not found in Saccharomyces cerevisiae. Among them, Saccharomyces kudriavzevii has good potential for aroma-compound production, fermentations and other biotechnological applications, but it is less adapted to stressful industrial conditions. This report studied S. kudriavzevii relative osmosensitivity and its capacity for active glycerol uptake. The results obtained (on the activity and physiological function of S. kudriavzevii glycerol transporter) may contribute to a further engineering of this species aiming to improve its osmotolerance.

Encapsulation of Saccharomyces cerevisiae in hydrogel particles based gellan ionically cross-linked with zinc acetate

The purpose of this study is to obtain ionically cross-linked gellan particles containing immobilized yeast cells. The zinc acetate was chosen as a cross-linking agent due to its beneficial role in the growth and nutrition of yeast cells and also due to the advantages of its use in fermentation processes. The physicochemical and morphological properties as well as the fermentative activity of the obtained particles were studied. The zinc acetate concentration has an influence on particles stability in water, on the mechanical stability and also on the swelling degree. The morphology of the obtained particles was analyzed by SEM and proves that the yeast cells are immobilized in large numbers in the polymeric matrix. The cell viability is maintained at high values after several fermentation cycles. These obtained micro-bioreactors were tested in terms of fermentative activity and the fermentation process was optimized by studying the influence of several factors. The gellan gum particles can be easily recovered by filtration and they can be reused in repeated fermentation cycles. The results obtained in the presence of these cross-linked particles are comparable to those achieved in the free yeast fermentation.

Production of bioethanol in sugarcane bagasse hemicellulosic hydrolysate by Scheffersomyces parashehatae, Scheffersomyces illinoinensis and Spathaspora arborariae isolated from Brazilian ecosystems.

This study aimed to evaluate new d-xylose-fermenting yeasts from Brazilian ecosystems for the production of second-generation ethanol. d-xylose-fermenting yeasts isolated from rotting wood and wood-boring insects were identified as the species Scheffersomyces parashehatae, Scheffersomyces illinoinensis, Spathaspora arborariae and Wickerhamomyces rabaulensis. Among the yeasts tested, those of Sc. parashehatae exhibited the highest ethanol production when cultivated on complex medium (Yp/set =0·437gg-1 ). Sheffersomyces illinoinensis and Sp. arborariae showed similar ethanol production in this assay (Yp/set up to 0·295gg-1 ). In contrast, in sugarcane bagasse hemicellulosic hydrolysate, Sc. parashehatae and Sc. illinoinensis exhibited similar ethanol production (Yp/set up to 0·254gg-1 ), whereas Sp. arborariae showed the lowest results (peak Yp/set =0·160gg-1 ). Wickerhamomyces rabaulensis exhibited a remarkable xylitol production (Yp/sxyl =0·681 gg-1 ), but producing low levels of ethanol (Yp/set =0·042gg-1 ). The novel d-xylose-fermenting yeasts showed promising metabolic characteristics for use in fermentation processes for second-generation ethanol production, highlighting the importance of bioprospecting research of micro-organisms for biotechnological applications. This study widens the scope for future researches that may examine the native yeasts presented, as limited studies have investigated these species previously.

Production of single cell protein (SCP) from food and agricultural waste by using Saccharomyces cerevisiae

Food waste is the single-largest component of the waste stream, in order to protect and safeguard the public health, useful and innovative recycling methods are investigated. The conversion of food wastes in value-added products is becoming a more economically viable and interesting practice. Food waste, collected in the distribution sector and citrus industries, was characterised for its potential as a raw material to use in fermentation processes. In this study, the production of single-cell protein (SCP) using food waste as a substrate was investigated. The purpose of this study has been to produce SCP from mixtures of food waste using Saccharomyces cerevisiae. The main fermentation test was carried out using a 25 l bioreactor. The utilisation of food waste can allow us to not only to reduce environmental pollution, but also to obtain value-added products such as protein supply for animal feed.

Ozonation as an effective way to stabilize new kinds of fermentation media used in biotechnological production of liquid fuel additives.

BackgroundIntermediates from processing sugar beets are considered an attractive feedstock for ethanol fermentation due to their high fermentable sugar content. In particular, medium prepared from raw sugar beet juice seems to be suitable for use in fermentation processes, but it is microbiologically unstable and requires sterilization.ResultsThis study investigates the effect of ozone treatment on the activity of microbial cells from Bacillus subtilis,Leuconostoc mesenteroides, Geobacillus stearothermophilus, Candida vini, and Aspergillus brasiliensis in raw sugar beet juice. Raw sugar beet juice contaminated with 105 cfu/mL of the microbial strains was treated with gaseous ozone (ozone concentration in the oxygen stream 0.1 g O3/L O2, flow rate 6 L/h, 10–30 min, 18–20 °C). The number of microflora decreased to 0 cfu/mL after 30 min of ozone treatment in all studied samples.ConclusionsMedium prepared from raw sugar beet juice and sterilized by ozonation is suitable for use in fermentation processes.

Improving biomass production and saccharification in Brachypodium distachyon through overexpression of a sucrose-phosphate synthase from sugarcane

The substitution of fossil by renewable energy sources is a major strategy in reducing CO2 emission and mitigating climate change. In the transport sector, which is still mainly dependent on liquid fuels, the production of second generation ethanol from lignocellulosic feedstock is a promising strategy to substitute fossil fuels. The main prerequisites on designated crops for increased biomass production are high biomass yield and optimized saccharification for subsequent use in fermentation processes. We tried to address these traits by the overexpression of a sucrose-phosphate synthase gene (SoSPS) from sugarcane (Saccharum officinarum) in the model grass Brachypodium distachyon. The resulting transgenic B. distachyon lines not only revealed increased plant height at early growth stages but also higher biomass yield from fully senesced plants, which was increased up to 52 % compared to wild-type. Additionally, we determined higher sucrose content in senesced leaf biomass from the transgenic lines, which correlated with improved biomass saccharification after conventional thermo-chemical pretreatment and enzymatic hydrolysis. Combining increased biomass production and saccharification efficiency in the generated B. distachyon SoSPS overexpression lines, we obtained a maximum of 74 % increase in glucose release per plant compared to wild-type. Therefore, we consider SoSPS overexpression as a promising approach in molecular breeding of energy crops for optimizing yields of biomass and its utilization in second generation biofuel production.

Biotransformation in Temperate Climate Fruit: A Focus on Berries

Berry fruits, cultivated in temperate zones, are popularly used in the human diet. With the increase in production and consumption, the development of food industry is oncoming in the sense of developing new products that can meet market needs, in addition to the development new formulations, enhancing the industrial waste and bio-transforming it to generate high value-added products is fundamental. The use of fermentation processes to increase the level of functional compounds and the production of enzymes, antibiotics and flavorings is a good example.

Heterologously expressed Aspergillus aculeatus β-glucosidase in Saccharomyces cerevisiae is a cost-effective alternative to commercial supplementation of β-glucosidase in industrial ethanol production using Trichoderma reesei cellulases

Trichoderma reesei is a filamentous organism that secretes enzymes capable of degrading cellulose to cellobiose. The culture supernatant of T.reesei, however, lacks sufficient activity to convert cellobiose to glucose using β-glucosidase (BGL1). In this study, we identified a BGL (Cel3B) from T.reesei (TrCel3B) and compared it with the active β-glucosidases from Aspergillus aculeatus (AaBGL1). AaBGL1 showed higher stability and conversion of sugars to ethanol compared to TrCel3B, and therefore we chose to express this recombinant protein for use in fermentation processes. We expressed the recombinant protein in the yeast Saccharomyces cerevisiae, combined it with the superb T.reesei cellulase machinery and used the combination in a simultaneous saccharification and fermentation (SSF) process, with the hope that the recombinant would supplement the BGL activity. As the sugars were processed, the yeast immediately converted them to ethanol, thereby eliminating the problem posed by end product inhibition. Recombinant AaBGL1 activity was compared with Novozyme 188, a commercially available supplement for BGL activity. Our results show that the recombinant protein is as effective as the commercial supplement and can process sugars with equal efficiency. Expression of AaBGL1 in S.cerevisiae increased ethanol production effectively. Thus, heterologous expression of AaBGL1 in S.cerevisiae is a cost-effective and efficient process for the bioconversion of ethanol from lignocellulosic biomass.

Immobilization of Selected Microbes at Some Selected Solid Supports for Enhanced Fermentation Process

Immobilization of macro molecules (such as enzymes) and micro-organisms can be generally defined as a procedure leading to their restricted mobility. Advantages of immobilization include easy separation of the enzymes/cells from the product and reuse of the enzymes/cells. In this research coconut tree leaf sheath was used to immobilize selected microbes which were used in fermentation tecnology. Coconut tree leaf sheath contains cellulose fiber layers which have cross linking between them. Sacchromyces cerevisiae was used as the microbial type due to widespread use in fermentation process. Microbes were entrapped within cellulose layers. Coconut tree leaf sheath was found to be an effecient solid support for immobilization. Immobilized microbes can be reused for fresh fermentation media. Immobilization can be carried out utilizing naturally avavilable coconut tree leaf sheath as a solid support, it`s usage is very cost-effective and eco-froiendly method rather than using synthetic or semi synthetic solid supports.

Screening of thermotolerant and thermophilic fungi aiming β-xylosidase and arabinanase production.

Plant cell wall is mainly composed by cellulose, hemicellulose and lignin. The heterogeneous structure and composition of the hemicellulose are key impediments to its depolymerization and subsequent use in fermentation processes. Thus, this study aimed to perform a screening of thermophilic and thermotolerant filamentous fungi collected from different regions of the São Paulo state, and analyze the production of β-xylosidase and arabinanase at different temperatures. These enzymes are important to cell wall degradation and synthesis of end products as xylose and arabinose, respectively, which are significant sugars to fermentation and ethanol production. A total of 12 fungal species were analyzed and 9 of them grew at 45 °C, suggesting a thermophilic or thermotolerant character. Additionally Aspergillus thermomutatus anamorph of Neosartorya and A. parasiticus grew at 50 °C. Aspergillus niger and Aspergillus thermomutatus were the filamentous fungi with the most expressive production of β-xylosidase and arabinanase, respectively. In general for most of the tested microorganisms, β-xylosidase and arabinanase activities from mycelial extract (intracellular form) were higher in cultures grown at high temperatures (35-40 °C), while the correspondent extracellular activities were favorably secreted from cultures at 30 °C. This study contributes to catalogue isolated fungi of the state of São Paulo, and these findings could be promising sources for thermophilic and thermotolerant microorganisms, which are industrially important due to their enzymes.

Investigation of the effect of brewer’s grain on formation of liquid-phase biologically active agents for plant industry and agriculture

The paper gives the results of investigating the fermentation and extraction method of producing from a peat-manure mass liquid-phase biologically active agents (bioagents, LPBs)with a varying content of brewer’s grain substituting peat in an amount from 5 to 25%. The optimal (10% of weight) use of the spent grain is proposed for the purposeful use of LPBs as a biological preparation for plant industry and agriculture. For utilizing brewer’s grain, it is suggested to maximize its use in fermentation processes.

Research highlights for issue 6: the applicability of model system research.

Research highlights for issue 6: the applicability of model system research.

TYPICAL MEXICAN AGROINDUSTRIAL RESIDUES AS SUPPORTS FOR SOLID-STATE FERMENTATION

Biological wastes contain several reusable substanc es of high value such as soluble sugars and fiber. Direct disposal of such wastes to soil or landfill causes serious environmental problems. Thus, the development of potential value-added processes for these wastes is highly attractive. These biological wastes can be used as support-substrates in Solid-State Fermentation (SSF ) to produce industrially relevant metabolites with great economical advantage. In addition, it is an environ ment friendly method of waste management. In this study were analyzed six different Mexican agro industrial residues to evaluate their suitability as support- substrate in SSF, between physicochemical properties that have included Water Absorption Index (WAI), Critical Moisture Point (CHP) and Packing Density (PD). The selection of an appropriate solid substrate plays a n important role in the development of an efficient S SF process. The results provided important knowledge about the characteristics of these materials reveal ing their potential for use in fermentation process es.

Immobilisation of yeast cells on carbon nanotubes

Carbon nanotubes are increasingly finding application in a wide range of industries. The focus of this study was to investigate the immobilisation of yeast cells onto carbon nanotubes, using a flocculation method, for possible use in fermentation processes. Carbon nanotubes, which are long thin cylinders of carbon, were used as artificial agents to induce flocculation of yeast cells. The immobilisation experiments on carbon nanotubes were conducted under different process conditions and compared with control experiments done on free cells. The resultant immobilised cells or flocs were recovered and freeze dried before analysis was performed. The flocculated cells were characterised by scanning electron microscopy to confirm that flocculation had occurred. Conditions that gave optimum flocculation on carbon nanotubes were found to be: a pH between 5.0 and 5.8, a temperature between 25 °C and 30 °C, an agitation speed of about 110 rpm, and a concentration of carbon nanotubes (in powder form) of between 44 mg/mL and 54 mg/mL. The addition of calcium ions and glucose decreased the rate of flocculation and delayed the onset of flocculation. Our study has demonstrated that carbon nanotubes have great potential to improve the flocculation capacity of brewer’s yeast.

Efficient use of lactose for the lac promoter-controlled overexpression of the main antigenic protein of the foot and mouth disease virus in Escherichia coli under fed-batch fermentation conditions.

Derivatives of the lac promoter (tac, pac, rac) belong to the strongest bacterial promoters which are frequently used for the induced overexpression of foreign genes in Escherichia coli. However, their use in fermentation processes is strongly restricted because of the high cost of the inducer iso-propyl-beta-D-thiogalactopyranoside (IPTG). The aim of this work was to investigate the possibility of using lac-derived promoters in high cell density processes resulting in a high yield of the induced recombinant protein if glucose is the main carbon and energy source. Lactose is tested as inducer of the main antigenic coat protein (VP1) of the foot and mouth disease (FMD) virus in a T7-RNA polymerase expression system. It was shown that lactose is able to induce the expression of the recombinant gene to an amount of the VP1 protein corresponding to 20% of the total cell protein.

Preparative purification ofTrichoderma reesei native and “core” cellobiohydrolase I by electrophoresis and chromatofocusing

The enzymes present in the cellulase complex produced by the fungus Trichoderma reesei have been the subject of considerable attention due to their potential for converting cellulosic materials into glucose for further use in fermentation processes. Cellobiohydrolase I (CBH I) is the major component of crude commercial fungal cellulase preparations and catalyzes the conversion of insoluble cellulose into cellobiose. We have been interested, recently, in the reduction of native and core'' CBH I (the primary structure of CBH I with a catalytic head region) and have needed to develop a method for their preparative purification. We now report that by using electrophoresis and chromatofocussing, preparative quantities of both native and core'' CBH I have been obtained. Since their pI values are different, milligram quantities of core'' CBH I can be generated and purified from the native enzyme by chromatofocussing within 2 hours. 13 refs., 7 figs., 2 tabs.

Monitoring of glucose in fermentation processes using a commercial glucose analyser

A commercial glucose analyzer, originally designed for monitoring of blood glucose in patients, was tested for use in fermentation processes. The system operates in such a way that the measured value is updated every 90 seconds. The measuring range of the system is 0–5 g glucose/l and the accuracy is ±7%. The response time was found to be approximately 6 min. The system was used to follow fermentations with two different microorganisms, Saccharomyces cerevisiae and Escherichia coli in media containing up to 5 g/l of glucose. The performance was fully satisfactory and the values had a very good correlation with off-line analyses.