Editorial

3 pages, 189 KiB

Open AccessEditorial

Microbial Biocontrol in the Agri-Food Industry

by Maurizio Ciani

Microorganisms 2023, 11(3), 552; https://doi.org/10.3390/microorganisms11030552 - 21 Feb 2023

Viewed by 1065

In recent years there has been a growing interest in the use of natural antimicrobial compounds to limit or avoid the use of chemical antimicrobials. Natural antimicrobial compounds can come from plants (essential oils) or from microorganisms (bacteriocins, mycocines, and active peptides). Despite [...] Read more.

In recent years there has been a growing interest in the use of natural antimicrobial compounds to limit or avoid the use of chemical antimicrobials. Natural antimicrobial compounds can come from plants (essential oils) or from microorganisms (bacteriocins, mycocines, and active peptides). Despite a wide range of possible applications, their exploitation at the industrial level is still limited and needs to be investigated. The actual and possible applications of natural antimicrobial compounds in agri-food are a growing research field. In addition to the use of antimicrobial compounds, microorganisms themselves can be used in the control of spoilage microorganisms along the entire production chain of the agri-food industry. Likewise, the papers collected in this Special Issue indicate the fast development of novelties in this research field. Full article

(This article belongs to the Special Issue Microbial Biocontrol in the Agri-Food Industry)

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15 pages, 2005 KiB

Open AccessArticle

Biocontrol of Non-Saccharomyces Yeasts in Vineyard against the Gray Mold Disease Agent Botrytis cinerea

by Alice Agarbati, Laura Canonico, Tania Pecci, Gianfranco Romanazzi, Maurizio Ciani and Francesca Comitini

Microorganisms 2022, 10(2), 200; https://doi.org/10.3390/microorganisms10020200 - 18 Jan 2022

Cited by 23 | Viewed by 2551

Abstract

Background: Botrytis cinerea (B. cinerea) is responsible for grape infection and damage to the winemaking and table grape sectors. Although anti-Botrytis chemicals are available, they are considered unsustainable for resistance phenomenon and adverse effects on the environment and human health. [...] Read more.

Background: Botrytis cinerea (B. cinerea) is responsible for grape infection and damage to the winemaking and table grape sectors. Although anti-Botrytis chemicals are available, they are considered unsustainable for resistance phenomenon and adverse effects on the environment and human health. Research is focused on developing alternative approaches, such as exploiting biological control agents (BCAs). In this context, 19 yeasts of the genera Cryptococcus, Aureobasidium, Metschnikowia, Kluyveromyces and Wickerhamomyces were tested as antimicrobial agents against B. cinerea development. Methods: A combination of in vitro tests based on dual-culture methods, volatile organic compound production assay, laboratory tests on grape berries (punctured and sprayed with yeasts) and field experiments based on yeast treatments on grapes in vineyards allowed the selection of two potential BCAs. Results: M. pulcherrima DiSVA 269 and A. pullulans DiSVA 211 exhibited the best ability to contain the development of B. cinerea, showing the severity, the decay and the McKinney index lower than a commercial biological formulation consisting of a mixture of two different A. pullulans strains, which were used as positive controls. Conclusions: The results indicated that the selected strains were effective BCA candidates to counteract B. cinerea in the field, applying them in the partial or total replacement of conventional treatments. Full article

(This article belongs to the Special Issue Microbial Biocontrol in the Agri-Food Industry)

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13 pages, 2236 KiB

Open AccessArticle

Biocontrol Potential of Chitin and Chitosan Extracted from Black Soldier Fly Pupal Exuviae against Bacterial Wilt of Tomato

by Violah Jepkogei Kemboi, Carolyne Kipkoech, Moses Njire, Samuel Were, Mevin Kiprotich Lagat, Francis Ndwiga, John Mwibanda Wesonga and Chrysantus Mbi Tanga

Microorganisms 2022, 10(1), 165; https://doi.org/10.3390/microorganisms10010165 - 13 Jan 2022

Cited by 21 | Viewed by 3823

Abstract

Globally, Ralstonia solanacearum (Smith) is ranked one of the most destructive bacterial pathogens inducing rapid and fatal wilting symptoms on tomatoes. Yield losses on tomatoes vary from 0 to 91% and most control measures are unaffordable to resource-poor farmers. This study investigated the [...] Read more.

Globally, Ralstonia solanacearum (Smith) is ranked one of the most destructive bacterial pathogens inducing rapid and fatal wilting symptoms on tomatoes. Yield losses on tomatoes vary from 0 to 91% and most control measures are unaffordable to resource-poor farmers. This study investigated the antimicrobial activities of chitin and chitosan extracted from black soldier fly (BSF) pupal exuviae against R. solanacearum. Morphological, biochemical, and molecular techniques were used to isolate and characterize R. solanacearum for in vitro pathogenicity test using disc diffusion technique. Our results revealed that BSF chitosan significantly inhibited the growth of R. solanacearum when compared to treatments without chitosan. However, there was no significant difference in the antibacterial activities between BSF and commercial chitosan against R. solanacearum. Soil amended with BSF-chitin and chitosan demonstrated a reduction in bacterial wilt disease incidence by 30.31% and 34.95%, respectively. Whereas, disease severity was reduced by 22.57% and 23.66%, when inoculated tomato plants were subjected to soil amended with BSF chitin and chitosan, respectively. These findings have demonstrated that BSF pupal shells are an attractive renewable raw material for the recovery of valuable products (chitin and chitosan) with promising ability as a new type of eco-friendly control measure against bacterial wilt caused by R. solanacearum. Further studies should explore integrated pest management options that integrate multiple components including insect-based chitin and chitosan to manage bacterial wilt diseases, contributing significantly to increased tomato production worldwide. Full article

(This article belongs to the Special Issue Microbial Biocontrol in the Agri-Food Industry)

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13 pages, 871 KiB

Open AccessArticle

Essential Oils from Indigenous Iranian Plants: A Natural Weapon vs. Multidrug-Resistant Escherichia coli

by Mohammadreza Pajohi Alamoti, Behnaz Bazargani-Gilani, Razzagh Mahmoudi, Anna Reale, Babak Pakbin, Tiziana Di Renzo and Ata Kaboudari

Microorganisms 2022, 10(1), 109; https://doi.org/10.3390/microorganisms10010109 - 05 Jan 2022

Cited by 11 | Viewed by 2583

Abstract

Aim of this study was to investigate the antimicrobial properties of herbal plant essential oils (EOs) from selected Iranian plant species such as Ferulago angulata, Zataria multiflora, Cuminum cyminum, and Mentha longifolia against antibiotic-resistant Escherichia coli (E. coli) [...] Read more.

Aim of this study was to investigate the antimicrobial properties of herbal plant essential oils (EOs) from selected Iranian plant species such as Ferulago angulata, Zataria multiflora, Cuminum cyminum, and Mentha longifolia against antibiotic-resistant Escherichia coli (E. coli) strains. For this purpose, the Escherichia coli strains, isolated from raw cow’s milk and local dairy products (yogurt, cream, whey, cheese, and confectionery products) collected from different areas of Hamedan province, Iran, were investigated for their resistance to antibiotics (i.e., streptomycin, tetracycline, gentamicin, chloramphenicol, ciprofloxacin, and cefixime). Thus, the E. coli strains were tested for their susceptibility to the above-mentioned essential oils. Regarding antibiotics, the E. coli strains were highly sensitive to ciprofloxacin. In relation to essential oils, the most effective antibacterial activity was observed with Zataria multiflora; also, the bacteria were semi-sensitive to Cuminum cyminum and Mentha longifolia essential oils. All strains were resistant to Ferulago angulata essential oil. According to the results, the essential oil of Zataria multiflora can be considered as a practical and alternative antibacterial strategy to inhibit the growth of multidrug-resistant E. coli of dairy origin. Full article

(This article belongs to the Special Issue Microbial Biocontrol in the Agri-Food Industry)

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15 pages, 1438 KiB

Open AccessArticle

Antimicrobial Activity of Chemically and Biologically Treated Chitosan Prepared from Black Soldier Fly (Hermetia illucens) Pupal Shell Waste

by Mevin Kiprotich Lagat, Samuel Were, Francis Ndwigah, Violah Jepkogei Kemboi, Carolyne Kipkoech and Chrysantus Mbi Tanga

Microorganisms 2021, 9(12), 2417; https://doi.org/10.3390/microorganisms9122417 - 23 Nov 2021

Cited by 21 | Viewed by 3719

Abstract

Globally, the broad-spectrum antimicrobial activity of chitin and chitosan has been widely documented. However, very little research attention has focused on chitin and chitosan extracted from black soldier fly pupal exuviae, which are abundantly present as byproducts from insect-farming enterprises. This study presents [...] Read more.

Globally, the broad-spectrum antimicrobial activity of chitin and chitosan has been widely documented. However, very little research attention has focused on chitin and chitosan extracted from black soldier fly pupal exuviae, which are abundantly present as byproducts from insect-farming enterprises. This study presents the first comparative analysis of chemical and biological extraction of chitin and chitosan from BSF pupal exuviae. The antibacterial activity of chitosan was also evaluated. For chemical extraction, demineralization and deproteinization were carried out using 1 M hydrochloric acid at 100 °C for 2 h and 1 M NaOH for 4 h at 100 °C, respectively. Biological chitin extraction was carried out by protease-producing bacteria and lactic-acid-producing bacteria for protein and mineral removal, respectively. The extracted chitin was converted to chitosan via deacetylation using 40% NaOH for 8 h at 100 °C. Chitin characterization was done using FTIR spectroscopy, while the antimicrobial properties were determined using the disc diffusion method. Chemical and biological extraction gave a chitin yield of 10.18% and 11.85%, respectively. A maximum chitosan yield of 6.58% was achieved via chemical treatment. From the FTIR results, biological and chemical chitin showed characteristic chitin peaks at 1650 and 1550 cm⁻¹—wavenumbers corresponding to amide I stretching and amide II bending, respectively. There was significant growth inhibition for Escherichia coli, Bacillus subtilis,Pseudomonas aeruginosa,Staphylococcus aureus, and Candida albicans when subjected to 2.5 and 5% concentrations of chitosan. Our findings demonstrate that chitosan from BSF pupal exuviae could be a promising and novel therapeutic agent for drug development against resistant strains of bacteria. Full article

(This article belongs to the Special Issue Microbial Biocontrol in the Agri-Food Industry)

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17 pages, 3386 KiB

Open AccessArticle

Effects of Moringa oleifera Leaf Extracts on Xanthomonas campestris pv. campestris

by Riccardo Fontana, Anna Caproni, Raissa Buzzi, Mariaconcetta Sicurella, Mattia Buratto, Francesca Salvatori, Mariangela Pappadà, Stefano Manfredini, Anna Baldisserotto and Peggy Marconi

Microorganisms 2021, 9(11), 2244; https://doi.org/10.3390/microorganisms9112244 - 28 Oct 2021

Cited by 9 | Viewed by 2588

Abstract

Xanthomonas campestris pv. campestris (Xcc) is a Gram-negative bacterium belonging to the Xanthomonodaceae family, causing black rot in crucifers. To control this pathogen, the study investigated the effect of different leaves extracts of Moringa oleifera Lam., a tropical plant, well known for its [...] Read more.

Xanthomonas campestris pv. campestris (Xcc) is a Gram-negative bacterium belonging to the Xanthomonodaceae family, causing black rot in crucifers. To control this pathogen, the study investigated the effect of different leaves extracts of Moringa oleifera Lam., a tropical plant, well known for its food properties and with countless applications in many different fields, from nutraceutical (hypoglycemic) to the cosmetic (sunscreen) properties. Nevertheless, several studies pointed to its antibacterial action against both Gram-negative and Gram-positive bacteria. Many bioactive compounds, including flavonoids, phenolic acids, alkaloids, isothiocyanates, tannins and saponins, contained in these extracts, are responsible for its countless activities. The analyses carried out in this study show that the methanolic, hydroalcoholic and hydroalcoholic maltodextrin extracts have both bacteriostatic and bactericidal effects at concentrations of 0.5, 0.5 and 0.1 mg/mL respectively. In particular, the study shows how all extracts can alter membrane permeability, to adversely affect swarming motility, and to alter biofilm formation in Xcc. The in planta experiments showed a reduction of the necrosis area in the infected radishes, although the ability of the extracts to be absorbed by root systems is yet to be understood, in order to reach the target point. Full article

(This article belongs to the Special Issue Microbial Biocontrol in the Agri-Food Industry)

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13 pages, 2058 KiB

Open AccessArticle

Screening of Lactic Acid Bacteria for the Bio-Control of Botrytis cinerea and the Potential of Lactiplantibacillus plantarum for Eco-Friendly Preservation of Fresh-Cut Kiwifruit

by Nicola De Simone, Vittorio Capozzi, Maria Lucia Valeria de Chiara, Maria Luisa Amodio, Samira Brahimi, Giancarlo Colelli, Djamel Drider, Giuseppe Spano and Pasquale Russo

Microorganisms 2021, 9(4), 773; https://doi.org/10.3390/microorganisms9040773 - 07 Apr 2021

Cited by 30 | Viewed by 3854

Abstract

Botrytis cinerea, responsible for grey mold, represents the first biological cause of fruit and vegetable spoilage phenomena in post-harvest. Kiwifruit is a climacteric fruit particularly prone to this mold infestation during storage. Lactic acid bacteria (LAB) are food-grade bacteria that can synthesize [...] Read more.

Botrytis cinerea, responsible for grey mold, represents the first biological cause of fruit and vegetable spoilage phenomena in post-harvest. Kiwifruit is a climacteric fruit particularly prone to this mold infestation during storage. Lactic acid bacteria (LAB) are food-grade bacteria that can synthesize several metabolites with antimicrobial activity and are, therefore, suggested as promising and eco-friendly resources for the bio-control of molds on fruits and vegetables. In this work, we propose the screening of a collection of 300 LAB previously isolated from traditional sourdoughs for their ability to counteract in vitro the growth of Botrytis cinerea CECT 20973. Only 2% of tested LAB strains belonging to Lactiplantibacillus plantarum species, exerted a strong antagonism against B. cinerea. The cell-free supernatants were partially characterized and results clearly indicated that high levels of lactic acid contributed to the antagonistic activity. PAN01 and UFG 121 cell-free supernatants were investigated as potential bio-control agents in a preliminary in vivo assay using freshly cut kiwifruits as a food model. The application of cell-free supernatants allowed to delay the growth of B. cinerea on artificially contaminated kiwifruits until two weeks. The antagonistic activity was greatly affected by the storage temperature (25 °C and 4 °C) selected for the processed fruits, suggesting the importance to include microbial-based solution in a broader framework of hurdle technologies. Full article

(This article belongs to the Special Issue Microbial Biocontrol in the Agri-Food Industry)

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14 pages, 1817 KiB

Open AccessArticle

Purification and Characterization of WA18, a New Mycocin Produced by Wickerhamomyces anomalus Active in Wine Against Brettanomyces bruxellensis Spoilage Yeasts

by Francesca Comitini, Alice Agarbati, Laura Canonico, Edoardo Galli and Maurizio Ciani

Microorganisms 2021, 9(1), 56; https://doi.org/10.3390/microorganisms9010056 - 28 Dec 2020

Cited by 14 | Viewed by 2894

Abstract

Wickerhamomyces anomalus strain 18, isolated from a natural underground cheese ripening pit, secretes a mycocin named WA18 that inhibits wine spoilage yeasts belonging to Brettanomyces bruxellensis species, with a broad-spectrum of activity. WA18 was purified, and the purified protein was digested with specific [...] Read more.

Wickerhamomyces anomalus strain 18, isolated from a natural underground cheese ripening pit, secretes a mycocin named WA18 that inhibits wine spoilage yeasts belonging to Brettanomyces bruxellensis species, with a broad-spectrum of activity. WA18 was purified, and the purified protein was digested with specific restriction enzymes (lysine K and arginine R cut sites). The LC–MS and LC–MS/MS analysis after enzymatic digestions revealed a molecular weight of 31 kDa. Bioinformatics processing and database research of digested pure killer protein showed 99% identity with a UDP-glycosyltransferase protein. Competitive inhibition assay of killer activity by cell-wall polysaccharides suggests that branched glucans represent the first receptor site of the toxin on the envelope of the sensitive target. The WA18 partially purified crude extract (PPCE) showed high stability of antimicrobial activity at the physicochemical conditions suitable for the winemaking process. Indeed, in wine WA18 was able to counteract B. bruxellensis and control the production of ethyl phenols. In addition, the strain WA18 was compatible with Saccharomyces cerevisiae in co-culture conditions with a potential application together with commercial starter cultures. These data suggest that WA18 mycocin is a promising biocontrol agent against spoilage yeasts in winemaking, particularly during wine storage. Full article

(This article belongs to the Special Issue Microbial Biocontrol in the Agri-Food Industry)

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