Substrate Sterilization Research Articles

Survey of mushroom consumption and the possible use of gamma irradiation for sterilization of compost for its cultivation in Southern Ghana

BackgroundMushroom cultivation is increasingly becoming a serious agribusiness in Ghana, especially at the time when entrepreneurship is being encouraged to reduce the pressure of employment in the government sector and also due to its nutritional and medicinal attributes.MethodsA survey was carried out using the rapid appraisal method to review the existing methods of sterilization, use of gamma radiation in substrate sterilization and food preservation, preference of mushrooms in Ghana by consumers and nutritional and medicinal attributes of the mushroom.ResultsThe survey demonstrated the popularity of drum (moist heat) technique of sterilization in Ghana. Majority (64%) of the respondents were dissatisfied with the method of sterilization of compost and spawn substrate, while 36% indicated the method was alright by them. Majority (82%) of the respondents had never heard of sterilization of substrates for cultivation and its subsequent preservation of food or mushroom by gamma irradiation technique. All consumers (100%) desired to see their favorite mushroom produced all year round, and this constituted a significant (p < 0.05) viewpoint. Furthermore, a significant (p < 0.05) majority (90%) of the respondents were all for promotion of the consumption of mushroom, while a small percentage (10%) were noncommittal.ConclusionInformation and knowledge on the gamma irradiation technique for substrate production and consumption patterns of P.ostreatus mushrooms were not widely disseminated as anticipated.

Use of Plant Extracts for Substrate Sterilization and Its Effect on Competitor Moulds and Biological Efficiency of Oyster Mushroom

Use of Plant Extracts for Substrate Sterilization and Its Effect on Competitor Moulds and Biological Efficiency of Oyster Mushroom

Efficiency of Developed Solid State Bioreactor 'FERMSOSTAT' on Cellulolytic and Xylanase Enzymes Production

FERMSOSTAT is a developed laboratory scale solid state fermenter. It is a horizontal stirrer drum bioreactor with about 70 L capacities. The fermenter is made of stainless steel which is anti-corrosive and non-toxic to the process organism. The fermenter is equipped with sets of control systems for temperature, agitation, aeration and also outlets for substrate sampling as well as inlets for inoculation and substrate additions. The uniqueness of this FERMSOSTAT system is its ability to carry out in situ substrate sterilization and extraction of enzymes at the end of SSF process. Moreover, the mixing system provided by FERMSOSTAT can be performed either full or half mixing as well as forward or reverse mixing. Furthermore, the mixing can be programmed to run at certain agitation rate and time interval during the fermentation process to prevent or reduce damage to the fungus mycelia. FERMSOSTAT is a developed SSF bioreactor and not an improvement of any existing one. The performances of FERMSOSTAT have been evaluated. Under optimum solid state fermentation conditions, about 63.4, 397 and 3.21 U/g of CMCase, xylanase and FPase activities were detected, which were higher compared to the tray system.

Action of an Argon/Water Vapor Plasma Jet in the Sterilization of Silicone Contaminated with Candida albicans

This work evaluates the influence of argon/water vapor plasma jet exposure time on surface sterilization of a silicone substrate contaminated with Candida albicans. For this purpose, gliding arc-type geometry was used to generate a nonthermal plasma jet at an applied power on the order of 20 W under water vapor carried by an argon flow of 5 L/min. C. albicans biofilms were grown on silicone plates with a 2cm2 area. Samples were treated with a plasmajet for different exposure times, resulting in the following sample groups: nontreated (A) or treated with plasma for 2 min (B), 5 min (C), 10 min (D), and 20 min (E). Experiments were performed in triplicate. To evaluate the action of the plasma jet on the contaminated samples, colony-forming units (CFUs) were counted before and after plasma exposure. Scanning electron microscopy (SEM) was used to analyze the morphological modification of the treated substrate, whereas Fourier transform infrared spectroscopy (FT-IR) was used to analyze the bare substrate after exposure to plasma. Optical emission spectroscopy was used to investigate the plasma species in the ultraviolet range. Results indicated reductions in CFUs of 42.4%, 74.2%, 83.7%, and 97.5% for groups B, C, D, and E, respectively. SEM images showed that groups D and E suffered more external cellular changes with shriveled, swollen, and/or deformed aspects. These effects can be attributed to reactive species in the plasma such as hydroxyl radicals (OH), which were increased considerably with the presence of water vapor in the mixture with argon gas. A quality change in the surface of the silicone material after 20 min of plasma treatment was observed with the results of the SEM and FT-IR analyses. Finally, the argon/water plasma jet promoted only a slight increase in substrate temperature (up to 310 K) for the investigated conditions, which is very convenient for thermal-sensitive material sterilization.

The use of sensory analysis in biotechnology of the cultivation of macromycetes

Sensory analysis is the most ancient and inexpensive method of assessing the quality of food products. Consumer demand for the fruit bodies of mushrooms is due to their unique taste and aroma. Profile methods of sensory analysis are used in quality control, for characterising the differences between food products and for determining the impact of various factors on the quality of the test product. The aim of this research is to study the influence of different types of substrates on the character and intensity of arom a of the dried fruit bodies of Pleurotus ostreatus (Jacq.: Fr.) Kumm. IBK–1535 using the sensory profile method. The substrates for the cultivation of mushrooms were selected from waste from the agricultural and wood processing industries: sunflower husks, wheat straw, waste from the cleaning of seed corn, and sawdust of deciduous trees and oak bark. The preparation and sterilization of substrates was performed according to standard techniques. During the process of cultivation we determined the culture-morphological indices of development of the mycelium: the duration of growth in the substrate, time of appearance of the primordia, the number of formed fruiting bodies of mushrooms, the average biomass of the fruiting bodies. We did not detect any significant differences between substrates in the growth rate of mycelia. The best culture-morphological indices of growth and development of mycelia were identified for the corn waste substrate. This substrate had the greatest number of primordia, while the lowest was for wheat straw. The mycelium of P. ostreatus IBK-1535 was white, fluffy, and denser on substrates of corn waste, sunflower husks and oak bark. The sensory profile analysis was performed according to ISO 6564:1885.1 g of dried fruiting bodies was crushed, placed in glass vials with stoppers and heated to +35…+40 °C for a better emission of volatile compounds. A five person degustation commission was trained to undertake the sensory analysis. First, using sensory analysis, the degustation commission determined the following descriptors of odour for the fruiting bodies of the fungi: mushroom, woody, grassy, sweet, sour. Then the intensity of the aroma of each sample was assessed on a five-point scale. The most characteristic mushroom aroma of the dried fruit bodies was obtained when oak bark was the substrate for cultivation. The samples of mushroom grown on sawdust and waste corn had a similar aroma. The samples obtained for sunflower husk and wheat straw had a slight mushroom aroma with grassy and sour notes. Thus, the use of the sensory profile method of analysis makes it possible to assess the degree of intensity of aroma of fruit bodies of higher edible mushrooms in relation to the conditions of their cultivation without having to use complicated instrumental methods of analysis. Moreover, sensory profile analysis can be used to monitor the odours and aromas of mushrooms, which are cultivated in artificial conditions, for the adjustment of the cultivation process and for conducting a rapid appraisal of the quality of mushroom products.

Protective effect of organic substrates against soil-borne pathogens in soilless cucumber crops

Protective effect of organic substrates against soil-borne pathogens in soilless cucumber crops

살균조건 및 UV-C 조사가 느타리버섯 병재배 오염율 감소에 미치는 영향

This study was conducted to reduce contamination ratio of oyster mushroom bottle cultivation. The optimalconditions of substrate sterilization for reducing of contamination ratio were at 121oC for 90min. In addition, UV-C irradiation isgood for lower contamination ratio to continue over 6 hours at cooling and inoculation room after sterilization. Thecontamination ratio and density of microorganisms of substrate were showed 0% after sterilization at 121oC for 90min.Trichoderma sp., main pathogen of mushrooms, was detected from substrate after sterilized during 2 or 4 hours at 101oC and 105oC,respectively. The amount of electricity used was the lowest at 121oC for 90min than that of other sterilization conditions. The UV-Cirradiation treatment was used UV-C lamp(40 watts) in the inoculation room(56m3). The density of bacteria did not detected after UV-C irradiation for 6 hours. And the death ratio of bacteria and Trichoderma sp. was 99.9% after UV-C irradiation for 6 hours. However,in the same UV-C irradiation time, the death ration of Cladosporium sp. was 90.9%. Therefore, the death ratio of fungi was lower thanthat of bacteria at the same UV-C irradiation treatment.

Impact of various sterilization methods on growth and yield of oyster mushroom (Pleurotus florida)

Oyster mushrooms (Pleurotus sp.) are one of the most appreciated mushrooms due to their high nutritional value, flavour, very good taste and medicinal value. It is grown in various lingo-cellulosic agro wastes thereby reduce the environmental pollution caused by its decomposition. In the process of mushroom cultivation, one of the most important aspects is the disinfection of the substrates. In the present study different substrate sterilization methods viz., hot water treatment for 30 min., autoclaving at 15lbs pressure for 20 min, treatment with formaldehyde solution (50ml/ ltr.water), treatment with bavistin (2g/ltr. water) and treatment with ordinary water (control) were investigated. Paddy straw was used as the substrate for mushroom cultivation. In the investigation, it was found that substrates sterilized by autoclaving was the best as it took less time for spawn run (15.0 days), pin head formation (20.3 days), fruiting body formation (23.3 day) and produced the highest mushroom yield per bed (892.35g) with biological efficiency of 89.24 per cent. Substrates sterilized with bavistin (890.25g/bed) and hot water (886.23g/bed) also produced good yield of mushroom which was comparable with those produced in autoclave sterilized substrate. Formaldehyde treatment behaved poorly as it took highest time for spawn run. As autoclaving of huge quantity of substrates in big farms is not convenient, chemical sterilization with bavistin can be practiced.

The Investigation of Virginiamycin-Added Fungal Fermentation on the Size and Immunoreactivity of Heat-Sensitive Soy Protein

The usage of soy protein for young monogastric animals is restricted due to potential allergens and high molecular weight. The investigation of fungi fermentation effect on soy protein has been interrupted by substrate sterilization. Virginiamycin at 0.05% was added together withAspergillus oryzaefor solid state fermentation (SSF) in unsterilized soy meal (SM). When compared toA. oryzaeSSF alone, virginiamycin did not cause the interference of fungal fermentation but elucidated the protein degradation. SDS-PAGE results showed that bothαandα′ subunits ofβ-conglycinin were degraded significantly. In addition, western blot results showed that the immunoreactive signals of soy protein were considerably reduced in virginiamycin-added fermentation with unsterilized SM. Furthermore, fungal fermentation increased total protein and essential amino acid contents, suggesting the value enhancement of SM products. Taken together, this study demonstrated for the first time that virginiamycin could help investigate fermentation effect on heat-sensitive soy protein. Fermented SM has several potential applications in feed industry.

Lipid recovery from a vegetable oil emulsion using microbial enrichment cultures.

BackgroundMany waste streams have a relatively high vegetable oil content, which is a potential resource that should be recovered. Microbial storage compound production for the recovery of lipids from lipid-water emulsions with open (unsterilized) microbial cultures was investigated in a sequencing batch reactor using a diluted vegetable oil emulsion as model substrate.ResultsAfter feeding, triacylglycerides (TAG) were accumulated intracellular by the microbial enrichment culture and subsequently used for growth in the remainder of the sequencing batch cycle. Roughly 50% of the added TAG could be recovered as intracellular lipids in this culture. The maximum lipid storage capacity of the enrichment culture was 54% on volatile suspended solids (VSS) mass basis in a separate fed-batch accumulation experiment. The microbial community was dominated by a lipolytic fungus, Trichosporon gracile, that was responsible for intracellular lipid accumulation but also a significant fraction of lipolytic and long chain fatty-acid-utilizing bacteria was present.ConclusionHerewith, we demonstrate an effective strategy for enrichment of a microbial community that can accumulate significant amounts of lipids from wastewaters without the need for sterilization of substrates or equipment. Further optimization of this process will make recovery of lipids from wastewater possible.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-015-0228-9) contains supplementary material, which is available to authorized users.

Minimization of Bacterial Contamination with High Solid Loading during Ethanol Production from Lignocellulosic Materials

Minimization of Bacterial Contamination with High Solid Loading during Ethanol Production from Lignocellulosic Materials

Abstract 18077: Endothelial Behavior and Signaling on Micro and Submicro- Patterned Titanium

Reestablishment of functional endothelium is crucial to long-term success in vascular stenting. However, numerous studies have shown potential for endothelial dysfunction on current drug eluting stents (DES), due to their reliance upon anti-inflammatory and immunosuppressive drugs for suppression of neointimal hyperplasia. We report results demonstrating that EC adhesion, proliferation, and morphology on Ti substrates can be enhanced significantly in vitro through surface patterning with gratings composed of periodic arrays of grooves with widths as small as 0.5 μm. We further asses the EC function on these surfaces. Patterned substrates were fabricated using our Ti deep reactive ion etching (Ti DRIE) process. After substrate sterilization, HECs were seeded and cultured for 1-3 days. Substrates were then rinsed with phosphate buffered solution (PBS) and adherent HECs were fixed and permeabilized and immuno-histo chemistry was performed and imaged using confocal fluorescent techniques, and processed. Figure 1 shows HECs aligned in the direction of sub-micron grooves and the corresponding signaling results. Activation of vWF, a vital anti-thrombotic, was significantly enhanced on all grating sub-patterns relative to unpatterned control (p value=0.05). Activation of eNOS, a potent vasodilator, generally increased with decreasing feature size. The phosphorylation of AMPK, which is reported to enhance cell polarity and division, was significantly higher on submicron-patterns of 0.75 and 0.5 μm (p value=0.5). Expression of VE Selectin, a metastatic cancer marker, was suppressed on most gratings. Finally, VCAM1, an anti-inflammatory, was negatively transcribed on sub-μm gratings (p value=0.05). These results demonstrate that nanopatterning can promote activation and suppression of atheroprotective and atheroscleotic biomolecules in vitro, thus suggesting promise for promoting native functionality in vivo.

Effect of different grain spawns and substrate sterilization methods on yield of oyster mushroom in Botswana.

The effect of three different grain spawns and two substrate sterilization methods on the spawn quality and yield of a hybrid of Pleurotus ostreatus x P. florida (Po x Pf) was studied on maize cobs supplemented with 20% wheat bran and 2% gram flour in a low technological mushroom house at Botswana College of Agriculture, Sebele. Sorghum grains proved to be better mycelium carriers (5.25, 7 days, 12 days and 75.4%) over wheat (2.45, 17 days, 16 days and 53.55%) and barley grains (3.46, 14 days, 13 days and 55.24%) in terms of mycelium growth vigor, colonization time, spawn running time of the substrate and yield of the oyster mushroom. Hot water treatment and steaming of substrate significantly reduced substrate contamination and improved mushroom yield as compared to the untreated control. Mushrooms grown on steamed substrates had significantly higher yield (BE: 69.4%) than those grown on substrates treated with hot water (BE: 53.3%).

Anti-Growth Factors Associated with Pleurotus ostreatus in a Submerged Liquid Fermentation

Aims: Previous studies had revealed that cultivation of Pleurotus ostreatus is often met with a lot of challenges ranging from environmental to biological factors which adversely affect the successful cultivation of the mushroom. Hence, a need to determine factors against mycelia colonization of substrate during mushroom’s cultivation. Methodology and Result: Conventional streak method was employed to establish the percentage inhibition as well as intercolony distance between the test organisms obtained from the infected substrate and mycelia of the mushroom during substrate colonization. The test organisms are: a fungus, Kutilakesopsis macalpineae and a bacterium, Pseudomonas tolaasii. The effect of pH and temperature on the mycelia growth of P. ostreatus was also investigated. There was a gradual increase in the percentage inhibition from 33.3 % at 24 h to 75.0 % at 168 h for K. macalpineae and 37.5 % at 24 h to 70.0 at 168 h for P. tolaasii. The inter-colony distance between the antagonists and the mushroom mycelium gradually decreased. Optical density of the mycelium growth was at its optimum at pH 4.5 and temperature of 25 °C respectively. I n vitro study also showed a significant increase in the optical density from 0.855±0.03 at 24 h to 1.316±0.02 at 168 h in the absence of test antagonist as against 0.812±0.06 and 0.79±0.02 at 24 h to 1.103±0.03 and 0.902±0.03 at 168 h when K. macalpineae and P.tolaasii were used as test antagonistic respectively. Conclusion, significance and impact of study: Sterilization of substrate is essential to avoid contamination during mycelia colonization. Also, slightly acidic medium and temperature control is necessary for high yield of fruit bodies.

Ethanol and Volatile Fatty Acid Production from Lignocellulose by Clostridium cellulolyticum

Clostridium cellulolyticum is capable of producing glycosyl hydrolase enzymes as well as fermentation products including ethanol and acetate. In this study, the potential of using C. cellulolyticum for ethanol and volatile fatty acid production from straw and grape pomace was examined. For rice straw, the effects of alkaline pretreatment and substrate sterilization prior to fermentation on products yields were also investigated. Effects of alkaline pretreatment and necessity for subsequent washing were tested for two types of grape pomace. For rice straw, the highest ethanol yield was 0.16 g/gVS from the straw pretreated with 10% sodium hydroxide loading at 121°C for 1 hour. Sterilization of the straw prior to fermentation was found to be not significant for ethanol production. Sterilization appeared to decrease native acetogen populations in the rice straw, resulting in lower acetic acid yields. The highest ethanol yield from grape pomace was of 0.09 g/gVS from the pretreated pomace. Pomace type (red or white) and washing were found to be not significant. Ethanol yields by C. cellulolyticum were lower than those from yeast in a simultaneous saccharification and fermentation system, but overall conversion of cellulose and hemicellulose was high, between 68 and 79%.

Studies on Sexual Reproductive Characteristics of Pteris vittata L. in Soil Culture

Abstract In order to understand sexual reproductive characteristics of an arsenic hyperaccumulator, Pteris vittata L., in soil culture and provide valuable suggestions for its commercial production, two experiments were performed focused on how storage time of spores, collection time, substrate sterilization methods, and culture conditions affect sexual reproductive efficiency. Results demonstrate that spores of P. vittata remain at high viability after several month storage, can live through hot water and spores collected in winter have a higher viability than those collected in spring. Furthermore, light is indispensable for gametophyte growth of P. vittata. During the gametophyte phase and the early sporophyte phase, P. vittata demonstrated a wide adaptability to differing light intensities, but grew best under 40% shade. Additionally, it grew in sand though it prefers fertile substrates. A proper combination of light, substrate, and densities of spores and gametophytes promises efficient reproduction.

Degradation and Nitrogen Release of Zein-based Bioplastic Containers

Abstract Environmental problems caused by petroleum-based plastics have led to interest in alternatives made from biodegradable polymers (bioplastics), but little effort has been made to evaluate horticultural containers made from these materials. We hypothesized the stability and longevity of containers made from polymers of the hydrophobic corn (Zea mays L.) protein, zein, is sufficient to make commercial use of zein-based containers feasible. Our objectives were to fabricate containers from zein, to determine longevity under conditions typical of horticultural production, and to identify limitations of the containers that might be overcome by further research. Zein-based, bioplastic containers of two wall thicknesses were filled with either a peat-based, soilless potting substrate or with coarse perlite and irrigated every 2 or 4 days. After 10 weeks, weight loss of containers was determined as a measure of their degradation. Containers filled previously with soilless substrate lost nearly twice as much weight as containers filled with perlite, and irrigation every 4 days led to greater weight loss than irrigation every 2 days. The containers released nitrogen (N) as they degraded; as much as 208 mg N·kg−1 was present in leachate after irrigation with water. In a second experiment, to simulate the potential practice of installing plants in the landscape without container removal, bioplastic containers of two sidewall thicknesses were filled with the soilless potting substrate and planted in either drained or saturated field soil, and the two substrates were either sterilized (autoclaved) or nonsterilized. After 12 weeks, containers in drained soils had greater weight loss than containers in saturated soils regardless of substrate sterilization treatment. Zein-based, bioplastic containers appear suitable for crops having production cycles of ≤ 3 months, and the containers will decompose and release N if installed with plants in the landscape. Further research is needed to increase the longevity of zein-based containers for crops with longer production cycles. In addition, the influence of containers made from zein on plant growth needs to be determined, and potential effects of degrading containers installed in the landscape on the establishment of transplants warrant investigation.

An aseptically operatable static solid state bioreactor consisting of two units

An aseptically operatable static solid state bioreactor consisting of two units

Optical emission spectroscopy characterization of oxygen plasma during degradation of Escherichia coli

Optical emission spectroscopy was applied for plasma characterization during sterilization of substrates contaminated with bacteria. The amount of 1010∕ml cells of Escherichia coli was carefully applied to glass substrates and exposed to oxygen plasma glow discharge at different pressures between 30 and 200Pa. Plasma was created in a glass discharge tube by an inductively coupled rf generator at the frequency of 27.12MHz and output power of about 250W. The electron temperature and plasma density were estimated with a double Langmuir probe. They were between 3 and 5eV and 2 and 35×1015m−3. Density of neutral oxygen atoms was measured with a catalytic probe, and was between 2 and 6×1021m−3. Optical emission spectroscopy was performed with a low resolution spectrometer. The emission from carbon monoxide and nitrogen molecules was used to monitor the evolution of bacteria degradation. Both signals expressed a well defined maximum corresponding to peak erosion of bacteria by plasma radicals. As the sterilization was accomplished, both CO and N2 lines fell below the detection limit of the spectrometer. The bacteria degradation was also monitored by scanning electron microscope (SEM) and culturing. The SEM images corresponded well with the evolution of CO and N2 lines so the optical emission spectroscopy found a reliable tool for monitoring the sterilization process.

Cucurbits under protected cultivation

Cucurbits under protected cultivation