1. The influence of polyphenolic compounds on anaerobic digestion of pepper processing waste during biogas and biomethane productionGregor Drago Zupančič, Anamarija Lončar, Jasmina Ranilović, Drago Šubarić, Mario Panjicko, 2024, original scientific article Abstract: Pepper processing waste has the potential to be used as a substrate in the process of anaerobic digestion, but because of its high polyphenol content, certain limitations are expected. During the determination of the biodegradability of pepper samples, a biogas potential of 687 L/kg DM was observed, as well as a biomethane potential of 401 L/kg DM. While both the testing of biodegradability and the process in the pilot scale progressed, it was observed that total polyphenol content in both cases decreased. Also, as far as individual polyphenols during the process in the pilot scale are concerned, it can be observed that at the end of the process no procyanidin A2, epicatechin, myricetin, and quercetin were detected. The observed concentration of the ferulic acid on the last
day of the process was 0.09 μg/g. Finally, it can be concluded that the presence of polyphenols did
not significantly affect the biogas potential of pepper waste. Due to its relatively stable biogas production,
as far as biogas production on the pilot scale is concerned, it can be concluded that pepper
processing waste has the potential to be used as a substrate for biogas production. Keywords: anaerobic digestion, polyphenols, ferulic acid, procyanidins, epicatechin, myricetin, quercetin Published in RUNG: 06.05.2024; Views: 1031; Downloads: 6 Full text (968,71 KB) This document has many files! More... |
2. Biopolymers produced by treating waste brewer’s yeast with active sludge bacteria : the qualitative analysis and evaluation of the potential for 3D printingGregor Drago Zupančič, Anamarija Lončar, Sandra Budžaki, Mario Panjicko, 2022, original scientific article Keywords: brewers’ yeast, active sludge bacteria, anaerobic digestion, biogas potential, biopolymer, 3D printing Published in RUNG: 01.08.2022; Views: 2399; Downloads: 32 Link to full text This document has many files! More... |
3. Anaerobic treatment of excess yeast and waste ethanol from alcohol free beer production for increase of renewable energy use in brewing industryGregor Drago Zupančič, Mario Panjicko, Goran Lukić, 2020, published scientific conference contribution Abstract: In the presented paper we have investigated how large quantities of excess yeast and periodical releases of waste ethanol influence the operation of the anaerobic treatment process in a UASB reactor. The process was tested in a pilot-scale reactor with a design organic load of 16.0 kg/m3/day of COD. Through various stages of the experiment, several possible scenarios were tested, excess yeast was added continuously with concentrations up to 3 vol. %, whereas waste ethanol was added in batches of up to 0.8 % of daily volume load several days a week. The intent was to test real conditions in the treatment process. The whole experiment lasted for 77 days, where the maximum organic load of 24.72 kg/m3/day was successfully achieved with no adverse effects on the efficiency of the reactor performance although it significantly surpassed the design load. The COD efficiency at maximum OLR was 83.1 %, whereas the average was 88.0 %. The average biogas production rate increased from 2,044 m3/m3/day to 4.927 m3/m3/day. The microbial community structure analysis showed significant shifts only in the archaeal community (25 – 30 %) as a good adaptation to the addition of substrates. Monitoring the model brewery in applying the addition of yeast and ethanol to the wastewater treatment showed a 110 % increase in biomethane production. The consequence of the increased biomethane production is that the natural gas substitute ratio could be increased from the current average of 10.7 % to potentially 20.1 %, which is a substantial step towards the goal of renewable energy use. Keywords: anaerobic digestion, biogas, brewery yeast, renewable energy, waste ethanol Published in RUNG: 10.06.2021; Views: 3304; Downloads: 12 Link to full text This document has many files! More... |
4. Anaerobic Co-Digestion of Ligno-Cellulosic degradation products - Wood Resin Residue from Tannin ProductionGregor Draago Zupančič, Mario Panjicko, Domagoj Eršek, Goran Lukić, Žiga Velišček, Martin Gojun, 2018, published scientific conference contribution Abstract: Tannin is a very versatile industrial material used for many applications. During tannin production, a residue is produced, which consists of 10 – 15 % sodium acetate solution with up to 10 % water-soluble wood resins by mass. Since it contains a high portion of acetate, it can be useful for anaerobic digestion to produce biomethane, whereas wood resins may exhibit inhibitory effects. In order to test the biodegradability of wood resin residue, several batch tests were performed with two approaches. In the first approach, co-digestion with corn-silage and animal waste was performed utilizing suspended biomass inoculum. In the second approach, co-digestion with pulp and paper wastewater was performed utilizing granular biomass inoculum. In the first approach, the results showed partial inhibition of degradation using mixtures of 25.6 % and total inhibition using 100.0 % of wood resin. Maximum biodegradability achieved was 83.4 %. In the second approach, the results showed partial inhibition of degradation using mixtures of 1.7 and 3.3 % of wood resin. Maximum biodegradability achieved was 64.3 %. Because the second approach enabled us to process larger quantities of wood resin (larger COD load), a pilot experiment of anaerobic co-digestion with pulp and paper wastewater was performed, utilising similar conditions to the considered full-scale treatment. The results showed COD degradation between 70.1 and 81.7 % and a potential increase in total produced biomethane of 36 – 39 %, with no significant adverse effects. Wood resin residue yielded 45 – 50 m3 of biomethane per tonne, which exhibits a good potential for biomethane production. If used for biomethane production in pulp and paper wastewater treatment, the valorisation value of the wood resin residue is between 54,500 € and 94,000 €, which makes the presented treatment also an economically viable option. Keywords: Anaerobic digestion, biomethane production, wood resin residue Published in RUNG: 11.03.2020; Views: 3969; Downloads: 0 This document has many files! More... |
5. Corn silage fungal-based solid-state pretreatment for enhanced biogas production in anaerobic co-digestion with cow manureMarina Tišma, Mirela Planinc, Ana Bucić Kojić, Mario Panjičko, Gregor Drago Zupančič, Bruno Zelić, 2018, original scientific article Abstract: The objective of this research was to use white-rot fungus Trametes versicolor for corn silage pretreatment and to investigate the effect of pretreatment on biogas productivity. Semi-continuous pilot-scale experiment, comprised of two experimental phases, was carried out. In the first phase, operational conditions of the full-scale biogas plant were reproduced at pilot-scale. In that phase, the reactor was daily fed with the mixture of cow manure,
digestate from industrial postfermentor, corn grits and ensiled corn silage, and the average methane generation
rate was 0.167 m3 CH4 per kgVS. In the second phase, corn grits and ensiled corn silage were replaced with corn
silage pretreated with T. versicolor, and the average methane generation rate increased up to 0.236 m3 per CH4 kgVS. The results of this study suggest that application of fungal-based solid-state pretreated corn silage has positive
effect on pH stability and increase the biogas productivity. Keywords: Semi-continuous anaerobic co-digestion
Fungal-based pretreatment
Corn silage
Cow manure Published in RUNG: 17.01.2018; Views: 4692; Downloads: 0 This document has many files! More... |
6. Biogas production from brewery spent grain as a mono-substrate in a two-stage process composed of solid-state anaerobic digestion and granular biomass reactorsMario Panjicko, Gregor Drago Zupančič, Romana Marinšek-Logar, Lijana Fanedl, Marina Tišma, Bruno Zelić, 2017, original scientific article Abstract: Anaerobic digestion of brewery spent grain as a mono-substrate was studied. Brewery spent grain is a substrate consisting largely of cellulose, hemicellulose and lignin, which are difficult to degrade anaerobically, mostly due to the presence of degradation products, such as phenolic compounds, which cause process inhibition. Therefore, a two-stage system was used for anaerobic digestion. Anaerobic digestion was phase separated in a solid-state anaerobic digestion reactor, where microbiological hydrolysis and acidogenesis occurred and in a granular biomass reactor where mostly methanogenesis was performed. The overall process exhibited total solids degradation efficiency between 75.9 and 83.0 %. Average specific biogas production was 414±32 L/kg, whereas biomethane production was 224±34 L/kg of added total solids. Granular biomass after adaptation exhibited stable operation at substrate C/N ratios in range 0.16 – 4.68. p-cresol was present in concentrations up to 45 mg/L and during the process was successfully degraded by granular biomass. The excellent adaptability of granular biomass was confirmed by 68.2 % shift in bacterial and a 31.8 % shift in archaeal community structure in a granular biomass reactor. The structure of the bacterial community from granular biomass reactor and solid-state anaerobic digestion reactor remained 79.4 % similar at the end of the experiment, whereas archaeal community was only 31.6 % similar. The process exhibited stable operation for 198 days, which shows that brewery spent grain can be successfully anaerobically digested and used for biogas production. Keywords: biogas production, brewery spent grain, C/N ratio, dry digestion, microbial biomass, solid-state anaerobic digestion Published in RUNG: 18.08.2017; Views: 5175; Downloads: 0 This document has many files! More... |
7. Biogas Production from Brewer’s Yeast Using an Anaerobic Sequencing Batch ReactorGregor Drago Zupančič, Mario Panjicko, Bruno Zelić, 2017, original scientific article Abstract: Renewable energy sources are becoming increasingly important in the beverage and food industries. In the brewing industry, a significant percentage of the used raw materials finishes the process as secondary resource or waste. The research on the anaerobic digestion of brewer’s yeast has been scarce until recent years. One of the reasons for this is its use as a secondary resource in the food industry and as cattle feed. Additionally, market value of brewer’s yeast is higher than its energy value. Due to the increase of energy prices, brewer’s yeast has become of interest as energy substrate despite its difficult degradability in anaerobic conditions. The anaerobic co-digestion of brewer’s yeast and anaerobically treated brewery wastewater was studied using a pilot-scale anaerobic sequencing batch reactor (ASBR) seeded with granular biomass. The experiments showed very good and stable operation with an organic loading rate of up to 8.0 kg/(m3·day), and with a maximum achieved organic loading rate of 13.6 kg/(m3·day) in a single cycle. A specific biogas productivity of over 0.430 m3/kg of the total chemical oxygen demand (COD) inserted, and total COD removal efficiencies of over 90 % were achieved. This study suggests that the brewer’s yeast can be successfully digested in an ASBR without adverse effects on the biogas production from brewer's yeast/wastewater mixtures of up to 8 % (by volume). By using the brewer's yeast in the ASBR process, the biogas production from brewery wastewater could be increased by 50 %. Keywords: anaerobic digestion, ASBR, biogas, brewer’s yeast Published in RUNG: 15.06.2017; Views: 6340; Downloads: 0 This document has many files! More... |
8. Anaerobic digestion of brewery spent grain as a mono-substrate in a two-stage anaerobic digestion using solid-state digestion reactor and granulated biomass reactorMario Panjicko, Gregor Drago Zupančič, Romana Marinšek Logar, Marina Tišma, Bruno Zelić, 2016, published scientific conference contribution (invited lecture) Abstract: Anaerobic digestion of brewery spent grain as a mono-substrate was studied. Anaerobic digestion was phase separated in solid state anaerobic digestion reactor, where mostly microbiological hydrolysis and acidogenesis and granular biomass reactor where mostly methanogenesis was performed. The overall process exhibited total solids degradation efficiency between 73.6 and 80.4%. Average specific biogas production was 424±36 L/kg, whereas biomethane production was 230±34 L/kg of brewery spent grain total solids. Granular biomass after adaptation exhibited stabile operation at C-N ratios as low as 0.2 – 0.3, which is rare in anaerobic digestion. P-cresol as a degradation product was present in concentrations up to 45 mg/L and during the process successfully degraded. The excellent adaptability of the granular biomass is confirmed by 67% shift in bacterial and a 32% shift in archaeal community structure in granular biomass reactor after 198 days of successful operation. Keywords: Anaerobic digestion, biogas production, brewery spent grain, microbial biomass, p-cresol degradation, solid state anaerobic digestion Published in RUNG: 21.10.2016; Views: 7032; Downloads: 0 This document has many files! More... |
9. Biogas production from brewery yeast in an EGSB reactorGregor Drago Zupančič, Milenko Roš, Miran Klemenčič, Matej Oset, Romana Marinšek-Logar, 2016, professional article Abstract: Experience over a five-year period of full throughput using anaerobic co-digestion of brewery yeast for biogas production is described in this contribution. The brewery, with a total amount of available yeast (0.7 v/v %), had a 26.2 % increase in COD load and a 38.5 % increase in biogas production resulting in an increase in the biomethane/natural gas substitution ratio in the brewery from 10 % to 16 %. Keywords: Anaerobic digestion, biogas production, brewery yeast, brewery wastewater, EGSB Published in RUNG: 21.04.2016; Views: 7405; Downloads: 0 This document has many files! More... |