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Agricultural activities produce large quantities of organic byproducts and waste rich in lignocellulosic materials, which are not sufficiently utilized. In this study, alternative agricultural waste products, namely, spent mushroom substrate (SMS) from the cultivation of edible Pleurotus ostreatus mushrooms and the roots of leafy vegetables from hydroponic cultivation (HRL), were evaluated for their potential to be used as substrates for the cultivation of Pleurotus citrinopileatus and their effects on the quality, the nutritional value, the chemical properties (lipid, protein, carbohydrate, ash, fatty acid and carbohydrate composition) and the bioactive content (total phenolic compounds and antioxidant activity) of produced mushrooms. SMS and HRL (in different ratios with and without additives) and wheat straw with additives (WS—control) were used. During incubation, the linear growth rate of the mycelium (Kr, mm/day) was measured and used for screening. Mushroom cultivation took place in bags, where several characteristics were examined: earliness (duration between the day of substrate inoculation and the day of first harvest) and biological efficiency (B.E. %, the ratio of the weight of fresh mushrooms produced per dry weight of the substrate × 100). Furthermore, this study aimed to investigate the effect of the protein extract (PE) and carbohydrate extract (CE) of P. citrinopileatus after in vitro digestion (fraction less than 3kDa: PE-DP-3; digestate fraction: CE-D, respectively) on the expression of antioxidant-related genes in the THP-1 cell line. The results showed that mushrooms grown on SMS 50%-HRL 40% had the fastest growth (6.1 mm/d) and the highest protein and lipid contents (34.7% d.w.; 5.1% d.w.). The highest B.E. (73.5%), total carbohydrate (65.7%) and total phenolic compound (60.2 mg GAE/g d.w.) values were recorded on the control substrate. Antioxidant activity was observed in all extracts; the total flavonoid content was low in the samples, and the maximum total triterpene value was detected in SMS 80%-HRL 20% (9.8 mg UA/g d.w.). In all mushrooms, linoleic acid (C18:2) was the main fatty acid (above 60%), and fructose was the dominant individual saccharide. In the investigation of the regulation pathway, NFE2L2 gene expression was upregulated only in the SMS 60%-HRL 40% intervention during incubation with CE-D samples. Additionally, the transcription levels of antioxidant-related genes, SOD1, CAT, HMOX1 and GSR, were increased in the SMS 60–30% intervention. Compared to WS, the alternative substrates are observed to trigger a pathway concerning CE that may resist oxidative stress. This study supports the utilization of agricultural byproducts through sustainable and environmentally friendly practices while simultaneously producing high-value-added products such as mushrooms. Therefore, alternative substrates, particularly those containing HRL, could serve as natural sources of antioxidant potential. [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate the effects of different dietary levels of spent mushroom substrate (SMS) at the expense of wheat straw (WS) on milk characteristics in dairy sheep. Thirty ewes at their final stage of lactation (145 ± 5 days after parturition) were randomly assigned into three groups; control (C), provided with a diet consisting of concentrates, alfalfa hay and WS, and SMS1 and SMS2, where WS was replaced by SMS at 50 or 100%, respectively. The experiment lasted for 28 days, and milk yield, composition, somatic cell count (SCC) and oxidative stability were monitored weekly, while milk fatty acid and immune cell profile were also determined on day 28. No significant differences were found in produced milk quantity, fat, protein, lactose, total solids non-fat, SCC and fatty acid profile between the experimental groups. However, milk oxidative stability was significantly improved as an effect of SMS (p < 0.001). At the same time, milk polymorphonuclear leukocyte percentage was decreased in SMS2 group (p < 0.05). As indicated, SMS seems to be a promising agro-industrial by-product for ewes' diet that could improve milk oxidative stability, without negatively affecting milk yield, composition and ewe health status, contributing in the context of sustainability, circular economy and protection of natural resources. [ABSTRACT FROM AUTHOR]

Background: The effect of substrate and strain on the nutritional and functional properties of mushroom flours and protein concentrates (PCs) has not thoroughly been investigated. Methods: The proteins of P. ostreatus flours (strains AMRL144 and 150) were isolated following alkaline extraction (pH 12) and isoelectric precipitation (pH 4) as it was determined by the solubility curves. The protein quality of the flours and PCs were evaluated by determining the protein solubility index (PSI) and their functional properties, such as water (WAC) and oil absorption capacity (OAC), foam capacity (FC), foam stability (FS) and emulsion stability (ES). The amino acid (AA) composition of the flours was determined by reversed-phase liquid chromatography after protein hydrolysis and o-phthalaldehyde derivatization. Results: The PSIs of the flours and PCs of P. ostreatus were comparable to those of soy protein flours and protein concentrates. The highest AA concentration was found for both strains when cultivated on the barley and oat straw (BOS) substrate, showing a similar trend as the protein content. A principal component analysis (PCA) indicated an impact of the strain on the functional properties. Conclusions: Both strains can produce high quality proteins especially when cultivated on wheat straw (WS). The FS was positively correlated with the P. ostreatus strain AMRL150 whereas the FC was positively correlated with AMRL144. [ABSTRACT FROM AUTHOR]

This study used a questionnaire to examine how academic staff members in Greece and Cyprus feel about the changes in undergraduate medical education during the COVID-19 pandemic. In general, e-learning was not considered an adequate way of teaching and was less enjoyable. Participants aged 31-40 years experienced more (P =.001), while staff in higher academic ranks less difficulty (P <.001) in adjustment. There was a small increase in workload, which was higher among respondents researching into COVID-19 (P =.001). During the pandemic, daily screen use >6 h was increased from 28.8% to 57.5%. The majority (74.2%) stated that scientific and educational training opportunities were not affected by the pandemic. In conclusion, the pandemic has induced important changes in undergraduate medical education. This new condition was considered adequate but not pleasant, with younger faculty members being more burdened. [ABSTRACT FROM AUTHOR]

Four wild "red" yeast strains (Rhodosporidium kratochvilovae FMCC Y70, R. toruloides NRRL Y-27013, R. toruloides NRRL Y-17902 and R. toruloides NRRL Y-6985) were cultured in shake flasks on industrial glycerol at an initial substrate (Gly0) concentration ≈ 50 g/L under nitrogen limitation. Strains NRRL Y-27013, NRRL Y-17902 and NRRL Y-6985 presented appreciable dry cell weight (DCW) and lipid synthesis (DCW up to 18–19 g/L containing lipids in quantities ≈ 47%, w/w). Strains NRRL Y-27013 and NRRL Y-6985 were further tested in higher Gly0 concentrations (≈90 g/L and ≈110 g/L) with the same initial nitrogen quantity as in the first ("screening") experiment. Both strains, despite the high Gly0 concentrations and C/N ratios (up to 120 moles/moles) imposed, presented significant DCW production (up to c. 29.0–29.5 g/L). Yeast biomass contained significant lipid (42–43%, w/w) and endopolysaccharide (up to 42%, w/w) quantities. Both lipids and endopolysaccharide quantities (in % w/w) noticeably increased as a response to the imposed nitrogen limitation. Lipids containing mainly oleic and palmitic acids constituted ideal candidates for biodiesel synthesis. Thereafter, the wastewaters derived from the lipid production process (lipid fermentation wastewaters—LFWs) were used as maceration waters in cultivations of edible and medicinal fungi, where novel (non-conventional) substrates were used in the performed cultures. CW (coffee residue + wheat straw), CB (coffee residue + beech wood shavings), OW (olive crop + wheat straw), OB (olive crop + beech wood shavings), RW (rice husk + wheat straw) and RB (rice husk + beech wood shavings) were soaked/sprayed with LFWs or tap water and utilized in the cultivation of Pleurotus, Ganoderma and Lentinula mushrooms. The impact of LFWs on the mycelial growth rate (mm/d) and biomass production was evaluated. The results show that regardless of the wetting method, the highest growth rates (6.2–6.6 mm/d) were noticed on RW and RB for Pleurotus eryngii and Ganoderma resinaceum, on OW, OB and RW for Ganoderma applanatum and on RW, OW and OB for Lentinula edodes. Nevertheless, high biomass production was obtained on substrates soaked with LFWs for Pleurotus ostreatus (RW: 443 mg/g d.w.), L. edodes (RB: 238 mg/g d.w.) and Ganoderma lucidum (RW: 450 mg/g d.w.). Overall, this study demonstrates the possibility of the industrial conversion of low-value agro-waste to mycelial mass and eventually to important food products. [ABSTRACT FROM AUTHOR]

The global market for citric acid (CA) is one of the biggest and fastest expanding markets in the food industry. The CA production employing microbial bioprocessing with efficient GRAS strains and renewable waste streams is in line with the European Union binding targets for resource efficiency, sustainable consumption-production, and low-carbon technologies. In this work, the potential of three novel wild-type Yarrowia lipolytica strains (namely LMBF Y-46, LMBF Y-47 and ACA-YC 5033) regarding the production of CA and other valuable metabolites was tested on glucose-based media, and the most promising amongst the screened strains (viz. the strain ACA-YC 5033) was cultured on glucose-based media, in which part of the fermentation water had been replaced by olive-mill wastewaters (OMWs) in a novel approach of simultaneous OMW valorization and bioremediation. In the first part of this study, the mentioned strains were cultured under nitrogen-limited conditions with commercial (low-cost) glucose employed as a sole carbon source in shake-flask cultures at an initial concentration (S0) ≈ of 50 g/L. Variable quantities of secreted citric acid (CA) and intra-cellular compounds (viz. polysaccharides and lipids) were produced. All strains did not accumulate significantly high lipid quantities (i.e., maximum lipid in dry cell weight [DCW] values ≈30% w/w were noted) but produced variable CA quantities. The most promising strain, namely ACA-YC 5033, produced CA up to c. 24 g/L, with a yield of CA produced on glucose consumed (YCA/S) ≈ 0.45 g/g. This strain in stirred tank bioreactor experiments, at remarkably higher S0 concentrations (≈110 g/L) and the same initial nitrogen quantity added into the medium, produced notably higher CA quantities, up to 57 g/L (YCA/S ≈ 0.52 g/g). The potential of the same strain (ACA-YC 5033) to bioremediate OMWs and to produce value-added compounds, i.e., yeast cells, CA, and intra-cellular metabolites, was also assessed; under nitrogen-limited conditions in which OMWs had partially replaced tap water and significant glucose concentrations had been added (S0 ≈ 100 g/L, simultaneous molar ratio C/N ≈ 285 g/g, initial phenolic compounds [Phen0] adjusted to ≈1.0 g/L; these media were similar to the OMWs generated from the traditional press extraction systems) the notable CA quantity of 60.2 g/L with simultaneous YCA/S = 0.66 g/g, was obtained in shake flasks, together with satisfactory phenolic compounds removal (up to 19.5% w/w) and waste decolorization (up to 47.0%). Carbon-limited conditions with Phen0 ≈ 1.0 g/L favored the production of yeast DCW (up to 25.3 g/L), with equally simultaneous interesting phenolic compounds and color removal. The fatty acid profile showed that cellular lipids were highly unsaturated with oleic, linoleic and palmitoleic acids, accounting for more than 80% w/w. This study proposed an interesting approach that could efficiently address the biotreatment of toxic effluents and further convert them into circular-oriented bioproducts. [ABSTRACT FROM AUTHOR]

Sugar-rich waste streams, generated in very high quantities worldwide, constitute an important source of environmental pollution. Their eco-friendly conversions into a plethora of added-value compounds through the use of microbial fermentations is currently a very "hot" scientific topic. The aim of this study, was to assess the potential of single cell oil (SCO), microbial mass and citric acid (CA) production by non-conventional yeast strains growing on expired ("waste") glucose. Six yeast strains (viz. Rhodosporidium toruloides DSM 4444, Rhodotorula glutinis NRRL YB-252, R. toruloides NRRL Y-27012, Yarrowia lipolytica LFMB Y-20, Y. lipolytica ACA-DC 50109 and Lipomyces starkeyi DSM 70296) were initially grown in shake flasks with expired glucose used as substrate under nitrogen limitation, in order to "boost" the cellular metabolism towards the synthesis of SCO and CA, and their growth response was quantitatively evaluated. Initial glucose concentration (Glc0) was adjusted at c. 50 g/L. Besides Y. lipolytica, all other yeast strains produced noticeable SCO quantities [lipid in dry cell weight (DCW) ranging from 25.3% w/w to 55.1% w/w]. Lipids of all yeasts contained significant quantities of oleic acid, being perfect candidates for the synthesis of 2nd generation biodiesel. The highest DCW production (=13.6 g/L) was obtained by L. starkeyi DSM 70296, while both Y. lipolytica strains did not accumulate noticeable lipid quantities, but produced non-negligible CA amounts. The most promising CA-producing strain, namely Y. lipolytica ACA-DC 50109 was further studied in stirred-tank bioreactor systems, while the very promising DCW- and SCO-producing L. starkeyi DSM 70296 was further studied in shake flasks. Both strains were grown on media presenting higher Glc0 concentrations and the same initial nitrogen quantity as previously. Indeed, L. starkeyi grown at Glc0 = 85 g/L, produced DCWmax = 34.0 g/L, that contained lipid =34.1% w/w (thus SCO was =11.6 g/L). The strain ACA-DC 50109 in stirred tank bioreactor with Glc0 ≈ 105 g/L produced CA up to 46 g/L (yield of CA produced on glucose consumed; YCA/Glc ≈ 0.45 g/g). Finally, in fed-batch bioreactor experiment, the significant CA quantity of 82.0 g/L (YCA/Glc = 0.50 g/g) was recorded. Concluding, "waste" glucose proved to be a suitable substrate for a number of non-conventional yeast strains. Y. lipolytica ACA-DC 50109 produced significant quantities of CA while L. starkeyi DSM 70296 was a very interesting DCW- and SCO-producing candidate. These strains can be used as potential cell factories amenable to convert glucose-based residues into the mentioned metabolic compounds, that present high importance for food, chemical and biofuel facilities. [ABSTRACT FROM AUTHOR]

Managing olive mill wastewater (OMW) is a major environmental problem. We followed two methods for OMW bioremediation: one with the white-rot fungus Pleurotus ostreatus alone and one with the fungus plus the microalga Chlorella vulgaris. To evaluate the potential use of both final products as soil amendments, in a pot experiment, we applied treated OMW to soil cultivated with Lactuca sativa, and we studied their short-term effects on the soil nematode community in terms of trophic and functional structure, metabolic footprint, genera composition, and interaction networks. We also applied non-treated OMW and simply water (control). The addition of non-treated OMW significantly reduced the abundance of all nematodes, and the network of interactions was the most fragmented and the least robust against future disturbance. The effect on trophic group abundances was similar but less pronounced when OMW was previously detoxified either by the fungus alone or by its combination with the alga. In the latter case, the phytoparasites were suppressed but the bacterivorous nematodes were not affected. However, the most cohesive and robust nematode network was formed in the soil that received the fungal-treated OMW. None of our OMW applications significantly changed community composition, none improved the already degraded status of the soil food web—which is attributed to the sandy texture of our soil—and none affected the growth of lettuce plants, perhaps because of the short duration of the experiment (30 days). Thus, our future research will aim to estimate the long-term impact of OMW. [ABSTRACT FROM AUTHOR]

In this study, the essential oil (EO) from the peel of the Greek citrus hybrid Citrus sinensis cv New Hall - Citrus aurantium was studied in terms of its antimicrobial properties as well as its effect on Saccharomyces cerevisiae. According to the analysis of the EO, 48 compounds are contained in it, with the main compounds being limonene, β-pinene, myrcene, α-pinene, valencene, and α-terpineol. As regards its antimicrobial properties, the EO was evaluated against nine human pathogenic microorganisms, six bacteria, and three fungi. Taking the results into account, it was apparent that Gram-negative bacteria were the most susceptible to the addition of the EO, followed by the Gram-positive bacteria, and finally the examined yeasts. The minimum inhibitory concentrations were found to be lower compared to other studies. Finally, the effect of the EO on the biochemical behavior of the yeast Saccharomyces cerevisiae LMBF Y-16 was investigated. As the concentration of the EO increased, the more the exponential phase of the microbial growth decreased; furthermore, the biomass yield on the glucose consumed significantly decreased with the addition of the oil on the medium. The addition of the EO in small concentrations (e.g., 0.3 mL/L) did not present a remarkable negative effect on both the final biomass concentration and maximum ethanol quantity produced. In contrast, utilization of the extract in higher concentrations (e.g., 1.2 mL/L) noticeably inhibited microbial growth as the highest biomass concentration achieved, maximum ethanol production, and yield of ethanol produced per glucose consumed drastically declined. Concerning the composition of cellular lipids, the addition of the EO induced an increment in the concentration of cellular palmitic, stearic, and linoleic acids, with a concomitant decrease in the cellular palmitoleic acid and oleic acids. [ABSTRACT FROM AUTHOR]

Valorization of lignocellulosic biomass, such as Spent Mushroom Substrate (SMS), as an alternative substrate for biogas production could meet the increasing demand for energy. In view of this, the present study aimed at the biotechnological valorization of SMS for biogas production. In the first part of the study, two SMS chemical pretreatment processes were investigated and subsequently combined with thermal treatment of the mentioned waste streams. The acidic chemical hydrolysate derived from the hydrothermal treatment, which yielded in the highest concentration of free sugars (≈36 g/100 g dry SMS, hydrolysis yield ≈75% w/w of holocellulose), was used as a potential feedstock for biomethane production in a laboratory bench-scale improvised digester, and 52 L biogas/kg of volatile solids (VS) containing 65% methane were produced in a 15-day trial of anaerobic digestion. As regards the alkaline hydrolysate, it was like a pulp due to the lignocellulosic matrix disruption, without releasing additional sugars, and the biogas production was delayed for several days. The biogas yield value was 37 L/kg VS, and the methane content was 62%. Based on these results, it can be concluded that SMS can be valorized as an alternative medium employed for anaerobic digestion when pretreated with both chemical and hydrothermal hydrolysis. [ABSTRACT FROM AUTHOR]

The potential of Rhodosporidium toruloides, Candida oleophila, Metschnikowia pulcherima, and Cryptococcus curvatus species to produce single-cell-oil (SCO) and other valuable metabolites on low-cost media, based on commercial-type xylose, was investigated. Rhodosporidium strains were further evaluated in shake-flasks using different lignosulphonate (LS) concentrations, in media mimicking waste streams derived from the paper and pulp industry. Increasing the LS concentration up to 40 g/L resulted in enhanced dry cell weight (DCW) while SCO production increased up to ~5.0 g/L when R. toruloides NRRL Y-27012 and DSM 4444 were employed. The intra-cellular polysaccharide production ranged from 0.9 to 2.3 g/L in all fermentations. Subsequent fed-batch bioreactor experiments with R. toruloides NRRL Y-27012 using 20 g/L of LS and xylose, led to SCO production of 17.0 g/L with maximum lipids in DCW (YL/X) = 57.0% w/w. The fatty acid (FA) profile in cellular lipids showed that oleic (50.3–63.4% w/w) and palmitic acid (23.9–31.0%) were the major FAs. Only SCO from batch trials of R. toruloides strains contained α-linolenic acid. Media that was supplemented with various LS concentrations enhanced the unsaturation profile of SCO from R. toruloides NRRL Y-27012. SCO from R. toruloides strains could replace plant-based commodity oils in oleochemical-operations and/or it could be micro- and nano-encapsulated into novel food-based formulas offering healthier food-products. [ABSTRACT FROM AUTHOR]

Vast quantities of side streams produced worldwide by the agricultural and food industry present an environmental challenge and an opportunity for waste upcycling in the frame of the circular bioeconomy. Fungi are capable of transforming lignocellulosic residues and wastes into a variety of added-value compounds with applications in functional food products, pharmaceuticals, chemicals, enzymes, proteins, and the emerging sector of nutraceuticals. The liquid state culture of fungi is an efficient and potentially scalable and reproducible biotechnological tool that allows the optimized production of fungal metabolites. Particularly, the utilization of agro-industrial by-products, residues, and wastes as a substrate for the liquid culture of macrofungi is suggested as an attainable solution in the management of these streams, contributing to climate change mitigation. This review presents recently published literature in the field of liquid state cultures of macrofungi using agro-industrial side streams, the different substrates, methods, and factors affecting their growth and metabolite production, as well as their applications, focusing on the variety of natural valuable compounds produced. [ABSTRACT FROM AUTHOR]

The production of various biochemical compounds such as proteins, glucans and glucanases, from the mycelium of four strains of Basidiomycetes species, Agaricus bisporus, Agaricus subrufescens, Pleurotus eryngii and Pleurotus ostreatus, during batch culture in shaking flasks, was studied. Fungi were cultured for 26 days in defined media with glucose as carbon source and were primarily evaluated for their ability to consume glucose and produce mycelial mass and intracellular polysaccharides (IPS). Results showed that on the 26th day of cultivation, P. ostreatus produced the maximum biomass (16.75 g/L), whereas P. eryngii showed the maximum IPS concentration (3.82 g/L). All strains presented a similar pattern in total protein production, with A. bisporus having the highest percentage of total proteins (36%, w/w). The calculated correlation coefficients among ribonucleic acid (RNA) vs. biomass (0.97) and RNA vs. protein (0.97) indicated a very strong relation between RNA and biomass/protein synthesis. The studied strains exhibited an increase in total glucan and glucanase (β-1,6) production during cultivation, with A. bisporus reaching the highest glucan percentage (8%, w/w) and glucanase activity (12.7 units/g biomass). Subsequently, processed analytical data were used in contour-graph analysis for data extrapolation to optimize future continuous culture. [ABSTRACT FROM AUTHOR]

Edible wild ascomycetes Morchella rotunda, M. vulgaris and M. conica were cultivated in liquid static and agitated flasks of sucrose and molasses substrates with a C/N ratio of 20 and 25. The impact of four substrates on the production and quality characteristics of morels was examined. Evaluation included determination of the dry mycelial mass, intra-cellular (IPS) and extra-cellular (EPS) polysaccharides, total phenolic (TPC) and antioxidant (TAC) components, proteins, as well as the degree of phenolic content reduction and decolorization of molasses. The influence of agitation conditions was also evaluated. Results showed that substrate consumption, biomass formation and secondary metabolites production were substrate, species, and C/N ratio dependent. Among species, M. conica achieved the maximum biomass (18.16 g/L) and IPS (4.8 g/L) production and significant phenolic reduction (56.6%) and decolorization (26.7%). The maximum EPS (3.94 g/L) was noted by M. rotunda, whereas TPC (32.2 mg/g), TAC (6.0 mg/g) and cellular protein (7.6% w/w) were produced in sufficient amounts. These results strongly support the use of Morchella mushrooms as a biological detoxification agent of molasses in liquid fermentations and indicate their nutritional and medicinal value. [ABSTRACT FROM AUTHOR]

Three ascomycetes (Morchella vulgaris AMRL 36, M. elata AMRL 63, Tuber aestivum AMRL 364) and four basidiomycetes strains (Lentinula edodes AMRL 124 and 126, Agaricus bisporus AMRL 208 and 209) were screened for their ability to grow on liquid static flask cultures of glucose, glycerol, molasses and waste flour-rich hydrolysates with C/N ratio of 20 and produce biomass, exopolysaccharides and lipids. The profile of lipid fatty acids was also assessed. Selected strains were furthermore cultivated in C/N = 50. Results showed that substrate consumption, biomass formation and secondary metabolites production were strain, substrate and C/N ratio dependent. The maximum biomass (X), lipid (L) and exopolysaccharides (EPS) values noted were Xmax = 25.2 g/L (C/N = 20; molasses) and Lmax = 6.51 g/L (C/N = 50; rice cereal hydrolysates) by T. aestivum strain AMRL 364 and EPSmax = 2.41 g/L by M. elata strain AMRL 63 (C/N = 50; molasses), respectively. When C/N ratio of 50 was applied, biomass, lipid production and substrate consumption seem to be negatively affected in most of the trials. The adaptation and capability of the mushroom strains to be cultivated on substrates based on agro-industrial waste streams and infant food of expired shelf date offers the opportunity to set a circular oriented bioprocess. [ABSTRACT FROM AUTHOR]

A new yeast wild-type Yarrowia lipolytica isolate presented efficient growth on glycerol. During flask cultures, nitrogen limitation led to the secretion of sugar-alcohols as the major metabolites of the process (mannitol, arabitol and erythritol), whereas insignificant quantities of citrate were synthesized. Although in some instances high initial glycerol concentrations were employed (≈150 g/L), remarkable glycerol assimilation and polyol secretion was observed. Total polyols ≈ 52 g/L (conversion yield on glycerol consumed = 0.43 g/g) was recorded in the flask experiments. The sugar-alcohol production bioprocess was successfully simulated with the aid of a modified Velhlust–Aggelis model that fitted very well with the experimental data, while optimized parameter values seemed to be quite consistent. In bioreactor trials, a noticeable metabolic shift towards citric acid production was observed, while simultaneously insignificant polyol quantities were produced. In fed-batch bioreactor experiments, a total citric acid quantity ≈ 102 g/L was recorded—one of the highest in the literature for wild-type Y. lipolytica strains. This metabolic transition was due to higher oxygen saturation into the medium that occurred in the bioreactor experiments compared with the flasks. Cellular lipids produced in the bioreactor trial contained higher concentrations of unsaturated fatty acids compared with those produced in flasks. [ABSTRACT FROM AUTHOR]

A total of 11 yeast strains of Yarrowia lipolytica , Metschnikowia sp. Rhodotorula sp. and Rhodosporidium toruloides were grown under nitrogen-limited conditions with crude glycerol employed as substrate in shake flasks, presenting interesting dry cell weight (DCW) production. Three of these strains belonging to Metschnikowia sp. accumulated significant quantities of endopolysaccharides (i.e. the strain V.V.-D4 produced 11.0 g/L of endopolysaccharides, with polysaccharides in DCW ≈ 63% w/w). A total of six Y. lipolytica strains produced either citric acid or mannitol. Most of the screened yeasts presented somehow elevated lipid and polysaccharides in DCW values at the early steps of growth despite nitrogen appearance in the fermentation medium. Lipid in DCW values decreased as growth proceeded. R. toruloides DSM 4444 cultivated on media presenting higher glycerol concentrations presented interesting lipid-accumulating capacities (maximum lipid = 12.5 g/L, maximum lipid in DCW = 43.0–46.0% w/w, conversion yield on glycerol = 0.16 g/g). Replacement of crude glycerol by xylose resulted in somehow decreased lipid accumulation. In xylose/glycerol mixtures, xylose was more rapidly assimilated from glycerol. R. toruloides total lipids were mainly composed of triacylglycerols. Total cellular fatty acid composition on xylose presented some differences compared with that on glycerol. Cellular lipids contained mainly oleic and palmitic acid. [ABSTRACT FROM AUTHOR]

Abstract: Waste bio-diesel derived glycerol was used as the sole carbon source by higher fungi; two Lentinula edodes strains were flask cultured in carbon-limited conditions and displayed satisfactory growth in media presenting weak agitation, pH 4.0 and temperature 25°C. Maximum biomass of 5.2g/l was produced. Mycelia were synthesized, containing around 0.1g of fat per g of biomass, with linoleic acid (Δ9,12C18:2) being the principal cellular fatty acid produced. Two Aspergillus niger strains were grown in nitrogen-limited flask cultures with constant nitrogen and two different initial glycerol concentrations into the medium. In 250-ml flask cultures, large-sized pellets were developed, in contrast with the trials performed in 2-l flasks. Nitrogen limitation led to oxalic acid secretion and intra-cellular lipid accumulation; in any case, sequential production of lipid and oxalic acid was observed. Initially, nitrogen limitation led to lipid accumulation. Thereafter, accumulated lipid was re-consumed and oxalic acid, in significant quantities, was secreted into the medium. In large-sized pellets, higher quantities of intra-cellular total lipid and lower quantities of oxalic acid were produced and vice versa. Maximum quantities of oxalic acid up to 20.5–21.5g/l and lipid up to 3.1–3.5g/l (corresponding to 0.41–0.57g of fat per g of biomass) were produced. Lipid was mainly composed of oleic (Δ9C18:1) and linoleic (Δ9,12C18:2) acids. [Copyright &y& Elsevier]

Five Agaricus bisporus commercial strains (S100, A15, F56, F40 and F62) were evaluated as regards their colonization rates, yields, quality characters and storability. Concerning their colonization performance, the mycelial growth rates examined in “race tubes” on sterile compost, as well as earliness in fructification did not differ significantly. Significantly lower was the yield of strain S100 compared to the yield of strains F62 and F56, which presented the greatest cumulative biological efficiency values. However, mushroom number and average weight presented negative relation. For the storage and quality study, mushrooms at the “closed-cap” stage packaged in 500-g plastic containers were stored for 5 days at 2C and 5 days at 18C (shelf life). The respiration behavior of the five strains was similar with the mass loss not exceeding 15% during storage at 2C and 40–50% at the end of the shelf life. Also, no differences in the whiteness and texture change were detected and a correlation between the period of pileus diameter increase and the respiration rate was found. According to their color and texture quality assessment, mushrooms deriving from the first four strains may be considered well acceptable at the end of the shelf life, whereas these from strain F62 just saleable. [ABSTRACT FROM AUTHOR]

Lentinula edodes mushrooms were produced by solid-state fermentation, using as substrates different mixtures of wheat straw (WS), corn-cobs (CC), and oak-wood sawdust (OS). Studies were conducted for evaluating their bio-transformation efficiency with respect to substrate colonization, time of sporophore production, biological efficiency, and mushroom nitrogen content, as well as basidiocarp number and size. First, the potential of residue-substrates to support early fructification was evaluated in glass-tubes. The mushrooms appeared 50–60 days after inoculation, with WS and CC promoting earlier sporophore initiation than did OS. A second experiment, where L. Edodes mushrooms were cultivated in ‘bag-logs’, revealed high productivity on CC and high mushroom protein content on OS-based substrates. However, WS appeared to promote early fructification and mushroom quality. Finally, mushroom production characteristics in tubes and bags were correlated with nitrogen content and C/N ratio of substrates. Early fructification was positively related to nitrogen content. Substrate mixtures with lower C/N ratio favoured earlier sporophore induction. [Copyright &y& Elsevier]

Dissipation of the fungicides famoxadone and trifloxystrobin in basidiocarps of Agaricus bisporus was studied in mushroom growing rooms. The mushroom samples taken at all three consecutive production flushes following single or split applications of the fungicides were extracted with solvents and the residues were determined by using a gas chromatograph equipped with an electron capture detector (GC-ECD). Recoveries from the fortified control samples ranged from 87 to 105%. Following drench applications at 0.1–1 g/m 2 of culture bed area, the highest famoxadone residue determined in basidiocarps was 0.1447 mg/kg. Analysis of trifloxystrobin revealed a quantitative relationship between the application rate (0.8–1.8 g/m 2 ) and the residue levels of both the parent compound and its acid metabolite. The maximal combined residues of trifloxystrobin and its metabolite were 0.1313 mg/kg. Short- and long-term dietary risk assessment for both fungicides was carried out using consumption data from World Health Organization and the UK Pesticide Safety Directorate's Ten Consumer Model. The potential acute and chronic residue intakes via mushroom consumption were below toxicologically significant indicators. [ABSTRACT FROM AUTHOR]

Abstract: The response of a commercial strain of Agaricus bisporus (L) Sing to the fungicides famoxadone, tebuconazole and trifloxystrobin was studied in vitro and in vivo. Mycelial growth of A. bisporus on casing medium in tubes was not affected by the reference fungicides carbendazim, prochloraz and mancozeb at 5mgL−1 and by famoxadone, tebuconazole and trifloxystrobin at 3.27, 0.1 and 1.0mgL−1, respectively. Overall biological efficiency of mushrooms obtained in pilot-scale cultivation was more affected by single applications of trifloxystrobin than famoxadone. The performance of the latter was comparable to prochloraz or carbendazim. Tebuconazole at 0.8gm−2 reduced severely total yield and caused pileus deformations. Regarding sporophore whiteness at harvest and after cool storage, carbendazim at 1.2gm−2 gave better results than prochloraz, famoxadone or trifloxystrobin applied at the same rate. A deviation in sporophore colour at harvest and after cool storage was observed only in the presence of tebuconazole at 1.2gm−2. Split applications of the fungicides did not favour whiteness retention under cool storage. [Copyright &y& Elsevier]

• Significant lipid and total dry biomass production were recorded by a novel Cryptococcus curvatus strain growing on commercial xylose. • Single cell oil produced was an appropriate material for the synthesis of high-quality biodiesel. • Lipid production bioprocess was successfully simulated by numerical models. • Biomass and laccase production of edible and medicinal mushrooms was achieved using lipid fermentation waste-waters. A rarely studied Cryptoccus curvatus strain (viz. NRRL Y-1511) was cultivated in shake-flask submerged nitrogen-limited experiments, with commercial xylose being employed as substrate and has been proved as quite appropriate for total biomass, lipid and endopolysaccharide production. A batch bioreactor trial compared to the equivalent shake-flask experiment showed larger amounts of total lipid and biomass produced. Total dry biomass of 26.1 g/L containing c. 30 % of lipids was synthesized. Endopolysaccharides in relatively high concentrations were synthesized in the early growth stages decreasing afterwards in favor of storage lipid synthesis. Lipid production bioprocess was successfully simulated by a modified Velruyten-Aggelis model and the optimized parameter values were found to be similar to those experimentally measured. Lipids contained mostly neutral fractions (triacylglycerols) and were rich in the fatty acid Δ9C18:1, constituting a suitable starting material for the synthesis of high-quality biodiesel. Within the frame of bio-refinery, lipid fermentation waste-waters were used as maceration waters for a novel mushroom cultivation process of Pleurotus ostreatus , Lentinula edodes and Ganoderma adspersum edible and medicinal mushrooms. These waste-waters were used for first time in mushroom cultivation process demonstrating positive effect on laccase and sporophore production by these mushroom species. [ABSTRACT FROM AUTHOR]

Spent mushroom substrate (SMS) of Pleurotus ostreatus was supplemented with wheat bran and soybean flour and used as substrate for a new cultivation cycle of the oyster mushrooms Pleurotus ostreatus and Pleurotus pulmonarius. The bioconversion efficiency of mushrooms produced over substrate (BE%) used and the chemical composition of sporophores were evaluated. The concentration of mycelial mass, crude exopolysaccharide content and laccase enzyme activity were also determined at the supplemented SMS before inoculation, at 50% and 100% of colonization stages in the new cultivation and in the final re-utilized SMS. The laccase enzyme was extracted to examine SMS potential for the dephenolization of olive mill and winery wastewaters. Results showed that both Pleurotus species exhibited BE over 185%, demonstrating this bioprocess could represent a promising strategy to convert SMS into nutritional food. Data also indicate the strong positive impact that SMS could have in the solid wastes' management and agribusiness enhancement. [ABSTRACT FROM AUTHOR]

Hearing loss is a common problem which, if remaining undetected during early childhood, could affect the patient’s linguistic and mental abilities permanently. Although recommended, mass hearing screening has so far been problematic or even impossible due to several reasons. The available otoacoustic emission devices appear to be effective tools for universal hearing screening. The aim of this study is to evaluate the reliability and practicability of a new device for recording click-evoked otoacoustic emissions (cEOEs) on a pediatric population. Sixty children aged between 6 days and 14 years were evaluated audiologically both by auditory brainstem responses (ABR) and otoacoustic emissions. The latter were obtained by using the well-known ILO88v3.92 otoacoustic analyser and a new, portable device (‘Echocheck’, Otodynamics Ltd, UK). Sensitivity and specificity of cEOEs recorded by ‘Echocheck’was found to be 93% and 91%, respectively, when compared to ABR results. Additionally, ‘Echocheck’ recordings were proved to be much easier to perform, needing considerably less time in comparison with those of the ILO88 system. In our opinion, ‘Echocheck’ as well as all similar portable devices – screeners – may represent a much-desired solution for implementing universal hearing screening programmes. [ABSTRACT FROM AUTHOR]

Morchella sp. is one of the most expensive mushrooms with a high nutritional profile. In this study, the polysaccharide content of Morchella species was investigated. Specifically, mycelium growth rate, biomass production, sclerotia formation, and glucosamine and total polysaccharides content of six Morchella species grown on a starch-based media were evaluated. Submerged fermentations in potato dextrose broth resulted in a glucosamine content of around 3.0%. In solid-state fermentations (SSF), using potato dextrose agar, a high linear growth rate (20.6 mm/day) was determined. Increased glucosamine and total polysaccharides content were observed after the formation of sclerotia. Biomass and glucosamine content were correlated, and the equations were used for the indirect estimation of biomass in SSF with agro-industrial starch-based materials. Wheat grains (WG), potato peels (PP), and a mixture of 1:1 of them (WG–PP) were evaluated as substrates. Results showed that the highest growth rate of 9.05 mm/day was determined on WG and the maximum biomass yield (407 mg/g) on WG–PP. The total polysaccharide content reached up to 18.4% of dried biomass in WG–PP. The results of the present study proved encouraging for the efficient bioconversion of potato and other starch-based agro-industrial waste streams to morel biomass and sclerotia eliciting nutritional and bioactive value. [ABSTRACT FROM AUTHOR]

Grape pomace, a by-product derived from winery industries, was used as fermentation media for the production of added-value products through the cultivation of two Pleurotus species. Solid-state (SSF), semiliquid (SLF), and submerged (SmF) fermentations were carried out using grape pomace as substrate. The effect of the different fermentations on the consumption of phenolic compounds, the production of mycelial mass and enzymes was evaluated using P. ostreatus and P. pulmonarius. The production of fungal biomass and enzymes was influenced by the fermentation mode. The maximum biomass values of ~0.5 g/g were obtained for both P. pulmonarius and P. ostreatus in SmF. Laccase production was induced in SSF and a maximum activity of 26.247 U/g was determined for P. ostreatus, whereas the highest endoglucanase activity (0.93 U/g) was obtained in the SmF of the same fungi. Analysis of phenolic compounds showed that both strains were able to degrade up to 79% of total phenolic content, regardless the culture conditions. Grape pomace was also evaluated as substrate for mushroom production. P. pulmonarius recorded the highest yield and biological efficiency of 14.4% and 31.4%, respectively. This study showed that mushroom cultivation could upgrade winery by-products towards the production of valuable food products. [ABSTRACT FROM AUTHOR]