Material Function of Mycelium-Based Bio-Composite: A Review

Mycelium-based bio-composite materials have been invented and widely applied to different areas, including construction, manufacturing, agriculture, and biomedical. As the vegetative part of a fungus, mycelium has the unique capability to utilize agricultural crop waste (e.g., sugarcane bagasse, rice husks, cotton stalks, straw, and stover) as substrates for the growth of its network, which integrates the wastes from pieces to continuous composites without energy input or generating extra waste. Their low-cost and environmentally friendly features attract interest in their research and commercialization. For example, mycelium-based foam and sandwich composites have been actively developed for construction structures. It can be used as synthetic planar materials (e.g., plastic films and sheets), larger low-density objects (e.g., synthetic foams and plastics), and semi-structural materials (e.g., paneling, flooring, furniture, decking). It is shown that the material function of these composites can be further tuned by controlling the species of fungus, the growing conditions, and the post-growth processing method to meet a specific mechanical requirement in applications (e.g., structural support, acoustic and thermal insulation). Moreover, mycelium can be used to produce chitin and chitosan, which have been applied to clinical trials for wound healing, showing the potential for biomedical applications. Given the strong potential and multiple advantages of such a material, we are interested in studying it in-depth and reviewing the current progress of its related study in this review paper.

Special aspects of plum clasterosporiosis development in Krasnodar Krai

В статье приведены результаты исследований развития клястероспориоза (возбудитель Stigmina carpophila (Lév.) M.B. Ellis, син. Clasterosporium carpophilum (Lév.) Aderh.) на сливе в Краснодарском крае в изменяющихся погодно-климатических условиях. В последнее десятилетие у возбудителя болезни выявлены изменения в биологии развития, что связано с участившимися экстремальными погодными условиями (количество температурных максимумов выше +30ºС, рост годового количества осадков - 100-300% нормы). Целью работы являлось выявление особенностей развития клястероспориоза сливы в Краснодарском крае в изменяющихся погодных условиях для оптимизации технологии защитных мероприятий. Исследования проводили в 2014-2019 гг. в центральной подзоне Прикубанской зоны Краснодарского края: ЗАО ОПХ «Центральное»; агробиологический стационар ФГБНУ «Северо-Кавказского федерального научного центра садоводства, виноградарства, виноделия» на сорте сливы Кабардинская ранняя. При выполнении работы использованы общепринятые и адаптированные методики. В результате изучения развития возбудителя клястероспориоза сливы впервые в крае был выявлен ряд параметров степени взаимосвязи развития патогена и погодных условий: более раннее заражение листьев - на 7-10 суток раньше; высокая первоначальная скорость развития болезни; сокращение продолжительности инкубационного периода на 2-3 суток. Выявлена оптимальная температура для роста мицелия гриба - +20…+24°С и температура, при которой происходит инфицирование +20…+26°С, при влажности воздуха 70-90 %. Определена температура, при которой отмечаются первые признаки болезни: при эпифитотии - +10-12°С, при умеренном распространении - +9-10°С. Результаты исследований позволят разработать практические подходы к усовершенствованию технологии защиты сливы от клястероспориоза. The article presents the results of studies of clasterosporiosis development (the infectious agent Stigmina carpophila (Lév.) M.B. Ellis, syn. Clasterosporium carpophilum (Lév.) Aderh.) on a plum in Krasnodar Krai in varied weather and climatic conditions. In the last decade, changes in the development biology were revealed in the pathogen of disease, which is associated with more frequent extreme weather conditions (the number of temperature peaks above +30 ºС, an increase in annual precipitation - 100-300% of the standard). The aim of work was to identify special aspects of plum clasterosporiosis development in Krasnodar Krai in changing weather conditions to optimize the technology of protective measures. The research was carried out in 2014-2019 in the central subzone of the Krasnodar Krai Kuban zone: ZAO experimental production farm "Tsentralnoye"; agrobiological station of the FSBSI North Caucasian Federal Scientific Center of Horticulture, Viticulture, Winemaking, on plum variety ‘Kabardinskaya Rannyaya’. Generally accepted and adapted techniques were used in the process of work. As a result of studying the development of plum clasterosporiosis infectant, a range of parameters of the degree of interrelation between the development of the pathogen and weather conditions was identified in the region for the first time: 7-10 days earlier infection of leaves; high initial rate of disease development; 2-3 days of incubation period reduction. The optimum temperature for the growth of the fungus mycelium was revealed - +20...+24°С, and the temperature at which the infection occurs - +20...+26°С, with an air humidity of 70-90%. We determined the temperature of first symptoms of disease - with epiphytotics - +10...+12°С, with moderate spread - + 9...+10°С. The research results will make it possible to develop practical approaches to improving the technology of protecting plums from clasterosporiosis.

Biological features and conditions of surface cultivating of a strain-producer of microbiopreparation Т-1 Trichoderma sp. against pathogen causing fusarium on oil flax

To develop technological regimen for production of microbiopreparations in a preparation form ‘wetting powder’ we studied biological features and conditions of surface cultivating of a strain-producer Т-1 Trichoderma sp. – an antagonist of pathogen Fusarium oxysporum Schlecht. emend. Shyd. et Hans. var. orthoceras (App. еt Wr.) Bilai and Fusarium poae (Peck) Wollenw., Lewis on oil flax. To study cultural and physiological qualities of the strainproducer we used agar and liquid mediums. Surface cultivation of a fungus on agar and liquid Rudakov’s medium at a temperature 25–30 оС was the most favorable for mycelium growth and spore formation. Stationary fungus cultivation on liquid medium with рН from 3 to 6 provided maximal mycelium growth with spore formation and the highest dry mass. Addition of starch into the Chapek’s nutrient medium caused maximal growth of fungus mycelium and increase of its dry mass. The best source of nitrogen for a fungus strain was corn extract. Rudakov’s and No1 mediums are optimal compound liquid nutrient mediums for a surface cultivation of the strain-producer. Optimal period of the surface cultivation of the fungal strain Т-1 Trichoderma sp. on liquid Rudakov’s nutrient medium was 10 days, and a volume of sowing culture to a nutrient medium – 2.0%.

Antifungal activity of Xenorhabdus spp. and Photorhabdus spp. against the soybean pathogenic Sclerotinia sclerotiorum

The fungus, Sclerotinia sclerotiorum, causes white mold disease and infects a broad spectrum of host plants (> 500), including soybean with yield losses of up to 70%. Biological control is a potential alternative for management of this severe plant pathogen, and relative to chemical fungicides, provides broad benefits to the environment, farmers and consumers. The symbiotic bacteria of entomopathogenic nematodes, Xenorhabdus spp. and Photorhabdus spp., are characterized by the production of antimicrobial compounds, which could serve as potential sources for new bio-fungicides. The objectives of this study were to assess cell-free supernatants (CFS) of 16 strains of these bacteria cultures on S. sclerotiorum mycelium growth; assess the volatiles of X. szentirmaii cultures on the fungus mycelium and sclerotium inhibition; and evaluate the X. szentirmaii cultures as well as their CFS on the protection of soybean seeds against the white mold disease. Among the 16 strains, the CFS of X. szentirmaii showed the highest fungicidal effect on growth of S. sclerotiorum. The CFS of X. szentirmaii inhibited > 98% of fungus growth from mycelium and sclerotia, whereas the volatiles generated by the bacterium culture inhibited to 100% of fungus growth and 100% of sclerotia production. The bacterial culture diluted to 33% in water and coated on soybean seeds inhibited S. sclerotiorum and protected soybean plants, allowing 78.3% of seed germination and 56.6% of plant development. Our findings indicate potential for a safe and novel control method for S. sclerotiorum in soybean. Moreover, this is the first study to indicate that volatile organic compounds from Xenorhabdus spp. can be used in plant disease suppression.

In vitro effect of four fungicides on Colletotrichum gloeosporioides causing anthracnosis on the Red Globe grape variety

Anthracnose is considered one of the most important diseases of grape crops. In this study, we evaluated the in vitro effect on potato dextrose agar (PDA) of four fungicides: benomyl (Benlate® 50 WP), carbendazim (Belico ® 500 SC), chlorothalonil (Odeon® 720 SC), and dodine (Syllit ® 400 SC) using three concentrations on a Colletotrichum gloeosporioides isolate. This species complex causes anthracnose on the Red Globe grape variety. The concentrations of each fungicide were: benomyl at 0.5, 0.25, and 1 g.L-1; carbendazim at 0.6, 0.3, and 1.2 mL.L-1; chlorothalonil at 2.4, 1.2, and 4.8 mL.L-1, and dodine at 1.6, 0.8, and 3.2 mL.L-1. Evaluated the inhibition of mycelial growth and the sporulation of the fungus. The fungus mycelium exposed to the commercial dose of the fungicides was observed using environmental scanning electron microscopy (ESEM). We used a completely randomized design with 13 treatments and five repetitions. Our results showed a degree of differential efficacy for the four fungicides and their effects were directly proportional to the dose used, benomyl and chlorothalonil being the most efficient in controlling the mycelial growth of the fungus. At the commercial dose, sporulation was inhibited at a higher rate by benomyl showing no statistically significant differences with the other products except chlorothalonil and dodine when the recommended dose was reduced by half. The damage observed by ESEM on the fungus mycelium ratified the effect obtained in vitro, i.e., deformed hyphae and irregular growth. The results of this study, complemented by electron microscopy, are promising for the appropriate selection of the best fungicides for controlling anthracnose on grape fruits, subject to the timely and correct diagnosis of the disease.

Antifungal Activity of Morinda citrifolia leaf extracts against Colletotrichum acutatum

Anthracnose is a plant disease that can infect a variety of plants worldwide. Fungal pathogen groups are the cause of anthracnose, one of which is Colletotrichum acutatum. Morinda citrifolia is famous for having antimicrobial activity. This study aims to determine the antifungal activity of M. citrifolia leaves extract against the growth of the fungus C. acutatum. The extract solvent used was 96% ethanol. The experiment consisted of five treatments (0%, 20%, 40%, 60% and propineb 0.1% as positive control). The method used in this study was the poisoned food technique. In this technique, C. acutatum was grown on PDA media mixed with M. citrifolia leaves extract. Antifungal activity was observed based on reduced mycelium growth compared to control. Observations were made every day by measuring the diameter of the fungus mycelium for eleven days. The analysis showed that 60% M. citrifolia leaves extract effectively inhibited the growth of the mycelium C. acutatum on the eleventh day of observation.

Preparation, uranium (VI) absorption and reuseability of marine fungus mycelium modified by the bis-amidoxime-based groups

Bis-amidoxime-based claw-like-functionalized marine fungus material (ZZF51-GPTS-DCDA-AM) was prepared for study to absorb the low concentration uranium (VI) from aqueous solution. A series of characterization methods such as SEM, TGA and FT-IR were applied for the functionalized materials before and after modification and adsorption. The experimental results suggested that the amidoxime groups were successfully grafted onto the surface of mycelium powder and provided the special binding sites for the absorption of uranium (VI). In the absorption research, uranium (VI) initial concentration, pH and equilibrium time were optimized as 40 mg L−1, 6.0, and 110 min by L43 orthogonal experiment, respectively, and the maximum absorption capacity of the prepared material was 370.85 mg g−1 under the optimum batch conditions. After five cycling process, the desorption rate and regeneration efficiency of the modified mycelium were found to be 80.29 % and 94.51 %, respectively, which indicated that the material had an adequately high reusability property as a cleanup tool. The well known Langmuir and Freundlich isotherm adsorption model fitting found that the modified materials had both monolayer and bilayer adsorption to uranium (VI) ions. Simultaneously, the pseudo-second-order model was better to illustrated the adsorption kinetics process. The enhanced adsorption capacity of uranium (VI) by the modified fungus materials over raw biomass was mainly owing to the strong chelation of amidoxime groups and uranium (VI) ions.

Fluid Flow in Cotton Textile: Effects of Wollastonite Nanosuspension and Aspergillus Niger Fungus

Aspergillus niger is a common contaminant in food industry, laboratories, and also a potential threat to biological works of art in museums. Cotton textiles have frequently been used in museums for canvas paintings. In the present project, the effect of Aspergillus niger on fluid flow rate of nanowollastonite-impregnated cotton textile specimens was investigated. Cotton specimens were impregnated with nanowollastonite (NW) suspension at four concentrations of 10%, 20%, 30%, and 40% to be further compared with control specimens. Results showed that fluid flow in cotton textile was as high as 361.3 cm3·s−1 due to its high porous structure and very low compactness of fibers (low density). Impregnation with NW did not have a significant effect on fluid flow in cotton textile. Exposure to Aspergillus niger increased fluid flow in control specimens as a result of deterioration of cotton fibers. Exposure of NW-impregnated specimens at concentrations more than 20% to Aspergillus niger did not have any significant effect on fluid flow. In control specimens, fungus mycelium penetrated deep into the texture of textile. However, in NW-impregnated specimens, the fungus could not penetrate into the texture and deteriorate the specimens. It was concluded that NW can be recommended for textile industry and also works of art as they protect cotton textiles against Aspergillus niger while, do not diminishi its dying and paintability properties.

Aspecte privind dezvoltarea bolii fainarea stejarului (Microsphaera Alphitoides) în arboretele de cvercinee

The fungal agent Microsphaera alphitoides is one of the main agents responsible for degradation of oak ecosystems in Moldova. The development and spread of the oak powdery mildew in the researched areas occurred during two stages of leaves infestation (primary infestation, in spring, through ascospori and secondary infestation, in summer, through conidia), directly depended on meteorological parameters and the presence of the source of infestation. The meteorological conditions in 2018 allowed the spread of the disease in oak stands, especially during the secondary infestation, when leaf infestation with the fungus mycelium was at medium level (inside the experimental surfaces) and reached a medium to strong level of infestation on trees at the forest edge. The high susceptibility of oak trees to this disease requires development of strategies to reduce the risk of "powdery mildew".