1
|
Microbiological Characterization of Greek Galotyri Cheese PDO Products Relative to Whether They Are Marketed Fresh or Ripened. FERMENTATION 2022. [DOI: 10.3390/fermentation8100492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Galotyri is the most popular traditional Greek PDO soft acid-curd cheese. This study compared the microbial numbers and types and characterized the lactic acid bacteria (LAB) biota of two artisan-type Galotyri PDO cheese varieties, one marketed fresh (Brand-K) and the other ripened (Brand-Z). Two retail batches of each cheese variety were analyzed, and a total of 102 LAB isolates were biochemically identified. LAB (7.2–9.3 log CFU/g) prevailed in all cheeses, followed by yeasts (5.8–6.8 log CFU/g). Typical starter strains of Streptococcus thermophilus and Lactobacillus delbrueckii were the most abundant species in all batches. However, the fresh Brand-K cheeses had 1–3 log units higher thermophilic starter LAB counts than the ripened Brand-Z cheeses, which contained a more diverse viable LAB biota comprising Lacticaseibacillus paracasei, Leuconostocmesenteroides, Lentilactobacillus (L. diolivorans, L. kefiri, L. hilgardii), Pediococcusinopinatus/parvulus, few spontaneous nonstarter thermophilic streptococci and lactobacilli, and Enterococcus faecium and E. faecalis at higher subdominant levels.Conversely, the fresh Brand-K cheeses were enriched in members of the Lactiplantibacillus plantarum group; other LAB species were sporadically isolated, including Lactococcus lactis. All retail cheeses were safe (pH 3.9–4.0). No Salmonella spp. or Listeria monocytogenes were detected in 25-g samples by culture enrichment; however, Listeria innocua and coagulase-positive staphylococci (850 CFU/g) survived in one ripened batch. Gram-negative bacteria were <100 CFU/g in all cheeses. In conclusion, ripening reduced the starter LAB viability but increased the nonstarter LAB species diversity in the present Galotyri PDO market cheeses.
Collapse
|
2
|
Liang J, Zhang H, Zhang P, Zhang G, Cai Y, Wang Q, Zhou Z, Ding Y, Zubair M. Effect of substrate load on anaerobic fermentation of rice straw with rumen liquid as inoculum: Hydrolysis and acidogenesis efficiency, enzymatic activities and rumen bacterial community structure. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 124:235-243. [PMID: 33636425 DOI: 10.1016/j.wasman.2021.02.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 01/20/2021] [Accepted: 02/07/2021] [Indexed: 06/12/2023]
Abstract
Rumen liquid is excellent to effectively degrade lignocellulose. In this study, the suitable rice straw load during anaerobic fermentation of rice straw with rumen liquid as inoculum was explored to improve volatile fatty acid (VFA) production. At 10.0% rice straw load, the highest VFA concentration reached 10821.4 mg/L, and acetic acid and propionic acid were the main components. In 10.0% rice straw load system, high concentration of soluble chemical oxygen demand (SCOD) was also observed, and the enzymatic activities at 48 h were higher than those at other rice straw loads. At 10.0% rice straw load, lower diversity and richness of rumen bacteria were found than those at other rice straw loads. Bacteroides, Prevotella, and Ruminococcus were the main rumen bacteria during rice straw degradation, and the rumen bacteria might secret effective lignocellulolytic enzymes to enhance the hydrolysis and acidogenesis of rice straw. The determination of suitable rice straw load will be beneficial to the application of rumen liquid as inoculum in actual production.
Collapse
Affiliation(s)
- Jinsong Liang
- College of Environmental Science & Engineering, Beijing Forestry University, Beijing 100083, China
| | - Haibo Zhang
- College of Urban and Rural Construction, Shanxi Agricultural University, Taigu 030801, China
| | - Panyue Zhang
- College of Environmental Science & Engineering, Beijing Forestry University, Beijing 100083, China.
| | - Guangming Zhang
- School of Energy & Environmental Engineering, Hebei University of Technology, Tianjin 300130, China
| | - Yajing Cai
- College of Environmental Science & Engineering, Beijing Forestry University, Beijing 100083, China
| | - Qingyan Wang
- College of Environmental Science & Engineering, Beijing Forestry University, Beijing 100083, China
| | - Zeyan Zhou
- College of Environmental Science & Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yiran Ding
- College of Environmental Science & Engineering, Beijing Forestry University, Beijing 100083, China
| | - Muhammad Zubair
- College of Environmental Science & Engineering, Beijing Forestry University, Beijing 100083, China
| |
Collapse
|
3
|
Yu Q, Feng L, Zhen X. Effects of organic loading rate and temperature fluctuation on the microbial community and performance of anaerobic digestion of food waste. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:13176-13187. [PMID: 33179190 DOI: 10.1007/s11356-020-11548-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 11/04/2020] [Indexed: 06/11/2023]
Abstract
Semi-continuous anaerobic fermentation of food waste was carried out using a solar-assisted heat reactor to explore effects of temperature fluctuation and organic loading rate (OLR: 2.0, 4.0, 6.0, 7.0 kg/(m3 day)VS on the reactor performance and microbial community structure. The results showed that the best methane production was achieved when OLR was 6.0 kg/(m3 day)VS because the reactors did not operate stably at 7.0 kg/(m3 day)VS. Compared with fluctuation of fermentation temperature, methane production at stable fermentation temperature increased by 21.72%, but higher power consumption occured. The results of high-throughput sequencing showed that OLR played a decisive role in succession of microbial community structure, while temperature fluctuation was more likely to affect microbial activity. When OLR was lower than 4.0 kg/(m3 day)VS, aceticlastic methanogens Methanosaeta were the dominant bacteria, while at 6.0 kg/(m3 day)VS, relative abundance of hydrogenotrophic methanogens Methanoregula and Methanospirillum increased.
Collapse
Affiliation(s)
- Qin Yu
- College of Energy and Environment, Shenyang Aerospace University, 37 Daoyi South Street, Shenyang, 110136, Liaoning, China
| | - Lei Feng
- College of Energy and Environment, Shenyang Aerospace University, 37 Daoyi South Street, Shenyang, 110136, Liaoning, China.
| | - Xiaofei Zhen
- School of New Energy and Power Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China
| |
Collapse
|
4
|
Remmas N, Roukouni C, Ntougias S. Bacterial community structure and prevalence of Pusillimonas-like bacteria in aged landfill leachate. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:6757-6769. [PMID: 28091993 DOI: 10.1007/s11356-017-8416-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 01/05/2017] [Indexed: 06/06/2023]
Abstract
Although several works have been performed from an engineering point of view, a limited number of studies have focused on microbial communities involved in the humification of aged landfill leachates. In this work, cultivation techniques, next-generation sequencing, and phospholipid fatty acid analysis were adopted to decrypt the diversity and the ecophysiological properties of the dominant microbiota in aged landfill leachate. Based on Illumina sequencing, Betaproteobacteria, Bacteroidetes, Actinobacteria, and Alphaproteobacteria dominated the aged landfill leachate. The main taxa identified at genus level were Pusillimonas-like bacteria and Leucobacter (41.46% of total reads), with all of them being also isolated through cultivation. The presence of Pusillimonas-like bacteria was also verified by the detection of cyclo17:0 and iso-19:0 fatty acids in aged landfill leachate microbiota. Despite that almost all bacterial isolates exhibited extracellular lipolytic ability, no particular specificity was observed in the type of substrate utilized. The prevalence of effective degraders, such as Pusillimonas-like bacteria, makes the aged landfill leachate an ideal source for isolation of novel microorganisms with potential in situ bioremediation uses.
Collapse
Affiliation(s)
- Nikolaos Remmas
- Laboratory of Wastewater Management and Treatment Technologies, Department of Environmental Engineering, Democritus University of Thrace, Vas. Sofias 12, 67100, Xanthi, Greece
| | - Charikleia Roukouni
- Laboratory of Wastewater Management and Treatment Technologies, Department of Environmental Engineering, Democritus University of Thrace, Vas. Sofias 12, 67100, Xanthi, Greece
| | - Spyridon Ntougias
- Laboratory of Wastewater Management and Treatment Technologies, Department of Environmental Engineering, Democritus University of Thrace, Vas. Sofias 12, 67100, Xanthi, Greece.
| |
Collapse
|
5
|
Li Y, Zhang Y, Liu Y, Zhao Z, Zhao Z, Liu S, Zhao H, Quan X. Enhancement of anaerobic methanogenesis at a short hydraulic retention time via bioelectrochemical enrichment of hydrogenotrophic methanogens. BIORESOURCE TECHNOLOGY 2016; 218:505-511. [PMID: 27394997 DOI: 10.1016/j.biortech.2016.06.112] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 06/24/2016] [Accepted: 06/28/2016] [Indexed: 06/06/2023]
Abstract
Anaerobic digestion (AD) is an important energy strategy for converting organic waste to CH4. A major factor limiting the practical applicability of AD is the relatively long hydraulic retention time (HRT) which declines the treatment efficiency of digesters. A coupling process of anaerobic digestion and 'electromethanogenesis' was proposed to enhance anaerobic digestion at a short HRT in this study. Microorganisms analysis indicated that the electric-biological reactor enriched hydrogenotrophic methanogens in both cathodic biofilm and suspended sludge, helping achieve the high organic removal (71.0% vs 42.3% [control reactor]) and CH4 production (248.5mL/h vs 51.3mL/h), while the additional electric input was only accounted for 25.6% of the energy income from the increased CH4 production. This study demonstrated that a bioelectrochemical enhanced anaerobic reactor could improve the CH4 production and organic removal at a short HRT, providing an economically feasible scheme to treat wastewater.
Collapse
Affiliation(s)
- Yang Li
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, PR China
| | - Yaobin Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, PR China.
| | - Yiwen Liu
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Zhiqiang Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, PR China
| | - Zisheng Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, PR China
| | - Sitong Liu
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, PR China
| | - Huimin Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, PR China
| | - Xie Quan
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, PR China
| |
Collapse
|