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López-García E, Romero-Gil V, Arroyo-López FN, Benítez-Cabello A. Impact of lactic acid bacteria inoculation on fungal diversity during Spanish-style green table olive fermentations. Int J Food Microbiol 2024; 417:110689. [PMID: 38621325 DOI: 10.1016/j.ijfoodmicro.2024.110689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 03/15/2024] [Accepted: 04/01/2024] [Indexed: 04/17/2024]
Abstract
This study delved into the evolution of fungal population during the fermentation of Spanish-style green table olives (Manzanilla cultivar), determining the influence of different factors such as fermentation matrix (brine or fruit) or the use of a lactic acid bacteria inoculum, on its distribution. The samples (n = 24) were directly obtained from industrial fermentation vessels with approximately 10.000 kg of fruits and 6.000 L of brines. Our findings showcased a synchronized uptick in lactic acid bacteria counts alongside fungi proliferation. Metataxonomic analysis of the Internal Transcribed Spacer (ITS) region unearthed noteworthy disparities across different fermentation time points (0, 24, and 83 days). Statistical analysis pinpointed two Amplicon Sequence Variants (ASV), Candida and Aureobasidium, as accountable for the observed variances among the different fermentation time samples. Notably, Candida exhibited a marked increase during 83 days of fermentation, opposite to Aureobasidium, which demonstrated a decline. Fungal biodiversity was slightly higher in brines than in fruits, whilst no effect of inoculation was noticed. At the onset of fermentation, prominently detected genera were also Mycosphaerella (19.82 %) and Apohysomyces (16.31 %), hitherto unreported in the context of table olive processing. However, their prevalence dwindled to nearly negligible levels from 24th day fermentation onwards (<2 %). On the contrary, they were replaced by the fermentative yeasts Saccharomyces and Isstachenkia. Results obtained in this work will be useful for designing new strategies for better control of table olive fermentations.
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Affiliation(s)
- Elio López-García
- Food Biotechnology Department, Instituto de la Grasa (CSIC), Ctra. Sevilla-Utrera, km 1. Building 46. Campus Universitario Pablo de Olavide, 41013 Seville, Spain
| | - Verónica Romero-Gil
- Department of Food Science and Technology, Agrifood Campus of International Excellence, University of Cordoba, 14014 Córdoba, Spain
| | - Francisco Noé Arroyo-López
- Food Biotechnology Department, Instituto de la Grasa (CSIC), Ctra. Sevilla-Utrera, km 1. Building 46. Campus Universitario Pablo de Olavide, 41013 Seville, Spain
| | - Antonio Benítez-Cabello
- Food Biotechnology Department, Instituto de la Grasa (CSIC), Ctra. Sevilla-Utrera, km 1. Building 46. Campus Universitario Pablo de Olavide, 41013 Seville, Spain.
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Pyne ME, Bagley JA, Narcross L, Kevvai K, Exley K, Davies M, Wang Q, Whiteway M, Martin VJJ. Screening non-conventional yeasts for acid tolerance and engineering Pichia occidentalis for production of muconic acid. Nat Commun 2023; 14:5294. [PMID: 37652930 PMCID: PMC10471774 DOI: 10.1038/s41467-023-41064-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 08/22/2023] [Indexed: 09/02/2023] Open
Abstract
Saccharomyces cerevisiae is a workhorse of industrial biotechnology owing to the organism's prominence in alcohol fermentation and the suite of sophisticated genetic tools available to manipulate its metabolism. However, S. cerevisiae is not suited to overproduce many bulk bioproducts, as toxicity constrains production at high titers. Here, we employ a high-throughput assay to screen 108 publicly accessible yeast strains for tolerance to 20 g L-1 adipic acid (AA), a nylon precursor. We identify 15 tolerant yeasts and select Pichia occidentalis for production of cis,cis-muconic acid (CCM), the precursor to AA. By developing a genome editing toolkit for P. occidentalis, we demonstrate fed-batch production of CCM with a maximum titer (38.8 g L-1), yield (0.134 g g-1 glucose) and productivity (0.511 g L-1 h-1) that surpasses all metrics achieved using S. cerevisiae. This work brings us closer to the industrial bioproduction of AA and underscores the importance of host selection in bioprocessing.
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Affiliation(s)
- Michael E Pyne
- Department of Biology, Concordia University, Montréal, QC, H4B 1R6, Canada
- Centre for Applied Synthetic Biology, Concordia University, Montréal, QC, H4B 1R6, Canada
- Department of Biology, University of Western Ontario, Ontario, Canada
| | - James A Bagley
- Department of Biology, Concordia University, Montréal, QC, H4B 1R6, Canada
- Centre for Applied Synthetic Biology, Concordia University, Montréal, QC, H4B 1R6, Canada
| | - Lauren Narcross
- Department of Biology, Concordia University, Montréal, QC, H4B 1R6, Canada
- Centre for Applied Synthetic Biology, Concordia University, Montréal, QC, H4B 1R6, Canada
- Amyris, Inc., Emeryville, CA, USA
| | - Kaspar Kevvai
- Department of Biology, Concordia University, Montréal, QC, H4B 1R6, Canada
- Centre for Applied Synthetic Biology, Concordia University, Montréal, QC, H4B 1R6, Canada
- Pivot Bio, Berkeley, CA, USA
| | - Kealan Exley
- Department of Biology, Concordia University, Montréal, QC, H4B 1R6, Canada
- Centre for Applied Synthetic Biology, Concordia University, Montréal, QC, H4B 1R6, Canada
- Novo Nordisk Foundation Center for Biosustainability, Lyngby, Denmark
| | - Meghan Davies
- Department of Biology, Concordia University, Montréal, QC, H4B 1R6, Canada
- Centre for Applied Synthetic Biology, Concordia University, Montréal, QC, H4B 1R6, Canada
- BenchSci, Toronto, ON, Canada
| | | | - Malcolm Whiteway
- Department of Biology, Concordia University, Montréal, QC, H4B 1R6, Canada
- Centre for Applied Synthetic Biology, Concordia University, Montréal, QC, H4B 1R6, Canada
| | - Vincent J J Martin
- Department of Biology, Concordia University, Montréal, QC, H4B 1R6, Canada.
- Centre for Applied Synthetic Biology, Concordia University, Montréal, QC, H4B 1R6, Canada.
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Benítez-Cabello A, Ramiro-García J, Romero-Gil V, Medina E, Arroyo-López FN. Fungal biodiversity in commercial table olive packages. Food Microbiol 2022; 107:104082. [DOI: 10.1016/j.fm.2022.104082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/19/2022] [Accepted: 06/15/2022] [Indexed: 11/29/2022]
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Cappato LP, Martins AMD, Ferreira EHR, Rosenthal A. Effects of hurdle technology on Monascus ruber growth in green table olives: a response surface methodology approach. Braz J Microbiol 2018; 49:112-119. [PMID: 29100931 PMCID: PMC5790643 DOI: 10.1016/j.bjm.2017.05.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 05/02/2017] [Accepted: 05/09/2017] [Indexed: 12/02/2022] Open
Abstract
An ascomycetes fungus was isolated from brine storage of green olives of the Arauco cultivar imported from Argentina and identified as Monascus ruber. The combined effects of different concentrations of sodium chloride (3.5–5.5%), sodium benzoate (0–0.1%), potassium sorbate (0–0.05%) and temperature (30–40 °C) were investigated on the growth of M. ruber in the brine of stored table olives using a response surface methodology. A full 24 factorial design with three central points was first used in order to screen for the important factors (significant and marginally significant factors) and then a Face-Centered Central Composite Design was applied. Both preservatives prevented fungal spoilage, but potassium sorbate was the most efficient to control the fungi growth. The combined use of these preservatives did not show a synergistic effect. The results showed that the use of these salts may not be sufficient to prevent fungal spoilage and the greatest fungal growth was recorded at 30 °C.
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Nonthermal pasteurization of fermented green table olives by means of high hydrostatic pressure processing. BIOMED RESEARCH INTERNATIONAL 2014; 2014:515623. [PMID: 25243146 PMCID: PMC4151865 DOI: 10.1155/2014/515623] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 07/26/2014] [Indexed: 11/17/2022]
Abstract
Green fermented olives cv. Halkidiki were subjected to different treatments of high hydrostatic pressure (HHP) processing (400, 450, and 500 MPa for 15 or 30 min). Total viable counts, lactic acid bacteria and yeasts/moulds, and the physicochemical characteristics of the product (pH, colour, and firmness) were monitored right after the treatment and after 7 days of storage at 20°C to allow for recovery of injured cells. The treatments at 400 MPa for 15 and 30 min, 450 MPa for 15 and 30 min, and 500 MPa for 15 min were found insufficient as a recovery of the microbiota was observed. The treatment at 500 MPa for 30 min was effective in reducing the olive microbiota below the detection limit of the enumeration method after the treatment and after 1 week of storage and was chosen as being more appropriate for storing olives for an extended time period (5 months). After 5 months of storage at 20°C, no microbiota was detected in treated samples, while significant changes for both HHP treated and untreated olives were observed for colour parameters only (minor degradation). In conclusion, HHP treatment may introduce a reliable nonthermal pasteurization method to extend the microbiological shelf-life of fermented table olives.
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