Mid Sweden University

Mycoremediation, the application of fungi for pollutant degradation, offers a sustainable solutionfor bioremediating contaminated environments. In mixed microbial settings, microbialcompetition can influence the efficiency of fungi by modulating pollutant degradation andnutrient availability. We investigated the bioremediation potential of boreal white-rot fungi(WRF) in fiberbank sediments, targeting organic pollutants such as polycyclic aromatichydrocarbons (PAHs) and potentially toxic elements (PTEs). Previously isolated and identifiedthirteen WRF species were screened in sterilized and unsterilized substrates to evaluate theeffects of microbial interactions on pollutant degradation and metal uptake. Key findingsrevealed that unsterilized fiberbank material supported superior PAH degradation, withTrametes hirsuta achieving up to 94% removal, suggesting synergistic interactions between WRFand native microbial communities. Conversely, sterilized substrates enhanced PTE uptake, withPhlebia tremellosa demonstrating significant accumulation of cadmium, bioconcentration factor(BCF) of 5.56 in sterile conditions and 0.85 in unsterile conditions, and lead, BCF of 1.65 understerile conditions, and 0.38 for unsterile conditions, this enhanced accumulation might be dueto reduced microbial competition. Statistical analyses confirmed significant differences (p <0.001) in pollutant removal and metal uptake between the two substrate conditions. Theseresults underline the importance of tailoring bioremediation strategies to substrate conditions.A dual approach, employing unsterilized substrates for organic pollutant degradation andsterilized substrates for metal accumulation, emerges as a promising framework. Futureapplications could focus on large-scale implementation of these strategies to rehabilitateindustrially contaminated sites like fiberbanks, balancing ecological sustainability withremediation efficacy.

Fiberbanks are organic-rich sediment deposits in aquatic environments, primarily formed through historical pulp and paper mill activities. These deposits consist of wood-derived fibrous materials and are contaminated with potentially toxic elements (PTEs) such as vanadium, chromium, cobalt, nickel, copper, zinc, arsenic, cadmium, and lead. The leaching of these contaminants into surrounding waters poses significant environmental and health risks, impacting aquatic ecosystems and potentially entering the food chain. Effective remediation of fiberbanks is crucial, particularly in Sweden and other regions with extensive wood-pulping industries. This study aims to evaluate the bioaccumulation capacities of 26 native Swedish white-rot fungi (WRF) species for the remediation of PTEs in fiberbank material. Fiberbank samples were collected from Sundsvall’s Bay in the Baltic Sea, while the fungal species were isolated from boreal forests in Västernorrland, Sweden. The fungi were cultured on Hagem agar medium with sterilized fiberbank material as the substrate. After two months, fungal biomass was analyzed for PTE uptake using inductively coupled plasma-mass spectrometry (ICP-MS). The results revealed significant variability (p < 0.001) in PTE uptake among fungal species. Phlebia tremellosa consistently demonstrated the highest bioconcentration factors for analyzed elements, with values for V (0.39), Cr (0.10), Co (1.81), Cu (1.54), Pb (1.65), Ni (1.28), As (0.83), Zn (3.61), and Cd (5.56). Other species, including Laetiporus sulphureus (0.09–4.78), Hymenochaete tabacina (0.08–4.52), and Diplomitoporus crustulinus (0.08–4.48), also exhibited significant bioremediation potential. These findings highlight the potential of native WRF species for PTEs remediation in fiberbanks and provide a foundation for mycoremediation strategies in contaminated environments. 

BACKGROUND: The strawberry tortrix, Acleris comariana (Lepidoptera: Tortricidae), is a destructive pest of strawberry in Denmark and southern Sweden. The efficacy of pheromone-based communication disruption of the species was examined in crop fields in southern Sweden. Due to the high cost of purchasing or synthesizing the pheromone (E)-11,13-tetradecadienal, lower quantities were applied per ha compared to similar mating disruption studies on other tortricid pests. RESULTS: When treating 1 ha within fields with 14 or 1.4 g of pheromone and using rubber septa as dispensers, trap catches were reduced by ≥98% versus control areas. When treating whole fields with 0.45–0.90 g/ha and using 1 g SPLAT droplets as dispensers, the effect on trap catch was less pronounced (63–95% reduction vs control fields). A corresponding reduction in larval numbers following the treatment was not achieved. Additional experiments revealed that males are more attracted to SPLAT droplets compared to trap lures, and aggregate near SPLAT droplets, indicating that low catches in traps were due to induced allopatry, a form of competitive disruption. In addition, female-baited traps were outcompeted when placed close to septum-baited traps. Pest densities were high, and the lack of control effect could be attributed to high encounter rates between the sexes despite the female competitive disadvantage, making mating disruption less efficient. CONCLUSION: Our data show the potential for pheromone-based control of A. comariana as part of integrated pest management, but the method needs optimization regarding density and strength of dispensers and ways to reduce the initial density of the pest to levels where competitive mechanisms of mating disruption can be efficient. 

Four-eyed bark beetles of the genus Polygraphus have been involved in large bark beetle outbreaks in different parts of the world, resulting in major economic losses. A striking example is the invasive species Polygraphus proximus which is a pest on Abies sibirica in Russia. In Sweden, Polygraphus poligraphus has been involved in bark beetle outbreaks on Norway spruce, Picea abies, together with the European spruce bark beetle Ips typographus. Two related species, Polygraphus punctifrons and Polygraphus subopacus are also present in Sweden. Recently, aggregation pheromones or pheromone components have been identified for these four Polygraphus species. However, questions remain regarding the complete composition of their pheromones, particularly for P. subopacus and P. proximus, whose aggregation pheromones appear to be very similar. In an attempt to better understand the chemical communication of these species, additional studies were conducted on P. poligraphus, P. punctifrons and P. subopacus using solid phase microextraction coupled with gas chromatography and mass spectrometry (SPME–GC–MS), electroantennography (EAG) as well as SPME–GC–MS and GC–MS with electroantennographic detection (EAD). Field experiments were also conducted. In P. punctifrons, some male-specific compounds were found in addition to those previously identified. In EAG and SPME–GC–MS/EAD studies, all three Polygraphus species responded strongly to grandisol. Using a chiral column, GC–MS/EAD revealed that they were able to detect both enantiomers of grandisol. In summary, this work presents our current understanding of the aggregation pheromones in four Polygraphus species and the challenges we have met in identifying species-specific pheromone blends for some of these species.

The pulp and paper industry in Sweden annually produce millions of tons of side-stream materials as black liquor, pulp and paper mill sludge, sulfite liquor and lignosulfonate. These lignocellulosic based materials can be more utilized today in biorefinery processes with microorganisms to produce high-value products as lipids, proteins and biofuels. In this work, we used five side-stream materials as carbon source in fermentation with two oleaginous yeasts, Lipomyces starkeyi and Rhodotorula toruloides. We analyzed lipid production, fatty acid profiles, inhibitors, phenolics, free sugars and metals before and after batch fermentation in 2 L bioreactors. Steam-exploded hardwood media was used as reference as it's known to be a good substrate for the oleaginous yeast species and after fermentation the lipid yield for R. toruloides was 17 % (w/w) and for L. starkeyi 13 % (w/w). The side-stream materials contained less than 30 % of free sugar compared to the reference media and the total lipid yield was thus less than 2.7 %, (w/w). R. toruloides utilized various sugars during fermentation and L. starkeyi mostly consumed glucose and xylose. Both yeast species also showed a possible ability to utilize various phenolics indicating their metabolic potential to convert depolymerized lignin along with wood-based sugars to lipids and proteins.

Background

Wastewater discharges from the old pulp and paper industry led to the accumulation of contaminated wood pulping fbers and debris—referred to as fberbanks (FB)—in the Baltic Sea and freshwater bodies across Sweden and other pulp-producing countries. These anthropogenic sediments are polluted with toxic metal(oid)s and persistent organic pollutants, and their decomposition releases greenhouse gases. Phytoremediation ofers a nature-based solution for the ex-situ treatment of these fbrous sediments, but they present unique challenges due to the abundant and unstable organic matter and aged pollution. This study aims to identify potential plant candidates and to address the limitations of fberbanks as a plants growing media for phytoremediation.In a greenhouse experiment, we assessed the performance of fve plant species (Brassica juncea, Brassica napus, Helianthus annuus, Hordeum vulgare, and Poa annua) grown in substrates formulated with fberbank. The evaluation included plant growth parameters, bioconcentration and uptake efciency of metal(oid)s (V, Cr, Co, Ni, Cu, Zn, As, Cd, and Pb), and the degradation of polycyclic and linear hydrocarbons.

Results

Despite initial concerns, fberbanks displayed favorable physical characteristics and a degree of fertility conducive to plant growth. Even though all tested species seeds could cope with fberbanks acute toxicity, H. vulgare and P. annua showed better tolerance to the fberbanks substrates and superior aerial biomass development, which promoted a highest toxic metal(oid)s uptake efciency, regardless of lower bioconcentration factors for most of the target elements. Zn (17.16–23.25 mg/kg of FB), Cu (4.18–6.48 mg/kg of FB) and Cr (1.05–1.36 mg/kg of FB) were most efectively taken up by these plants. The uptake of Co (0.04–0.18 mg/kg of FB) and Ni (0.05–0.17 mg/kg of FB) was lower. As (0.01–0.02 mg/kg of FB), Cd (0.02–0.06 mg/kg of FB), Pb (0.02–0.04 mg/kg of FB) and V (0.02–0.03 mg/kg of FB) phytoextraction was not signifcant. None of the species exhibited a signifcant removal of targeted organic pollutants.

Conclusions

Phytoremediation, either on its own or in combination with other strategies, shows promise for the remediation of fberbanks. However, further research is needed to understand how the organic matrix and long-term underwater aging of fberbanks afect pollutants bioavailability.

Decentralized composting is an emerging method for managing biowaste, engaging waste generators as active recyclers in the waste management cycle. Evaluating performance and identifying optimization opportunities within this composting framework is essential to maximize its benefits and address its challenges. In small-scale composters, fresh waste is continuously mixed with previously added materials, shifting the typical composting process. As with larger systems, the composition of the feedstock influences the temperature profile and the quality of the final product. The issue of whether to include animal-source waste remains controversial in the development of standards and program guidelines. On the other hand, evaluating a leachate recycling method could help prevent nutrient loss and mitigate environmental impacts when bulking agents are lacking. In this study, kitchen and garden wastes were composted in 500-L static composters under cold climate conditions. We examined obtained compost stability, maturity, and quality parameters to determine the effects of adding animal by-product waste and/or recycling leachate. Our findings indicate that including animal by-products allows reaching sanitation temperatures under cold weather conditions and that recycling leachates could reduce nutrient losses and alleviate environmental and other user concerns while improving temperature, stability, maturity, and product quality patterns in decentralized composting. 

Fiberbanks refer to a type of fibrous sediment originated by the forestry and wood pulping industry in Sweden. These anthropogenic sediments are significantly contaminated with potentially toxic elements, and a diverse array of organic pollutants. Additionally, these sediments are of environmental concern due to their potential role in greenhouse gas emissions. Given the environmental risks posed by these sediments, the development of effective remediation strategies is of critical importance. However, no specialized methods have been established yet for the cleanup of this specific type of contaminated sediments. To identify effective fungal species for the mycoremediation of the fiberbank substrate, we performed a detailed screening experiment. In this research, we primarily aimed at assessing both the growth capacity and the proficiency in degrading organic pollutants of 26 native white-rot fungi (WRF) species. These species were sourced from natural forest environments in northern Sweden. The experimental setup involved evaluating the WRF on plates containing fiberbank material with a central Hagem-agar disc to closely monitor the interaction of these species with fiberbank substrates. Among the fungi tested, Laetiporus sulphureus exhibited the highest growth area percentage at 72%, followed by Hymenochaete tabacina at 68% and Diplomitoporus crustulinus at 67%. For the removal of 2–3 ring polycyclic aromatic hydrocarbons (PAHs), Phellinus punctatus led with 68%, with Cystostereum muraii at 57% and Diplomitoporus crustulinus at 49%. Regarding the removal percentage of 4–6 ring PAHs, Diplomitoporus crustulinus showed the highest efficiency at 44%, followed by Phlebia tremellosa at 40% and Phlebiopsis gigantea at 28%. 

The syngas produced from biomass gasification is a great potential energy resource, which can well be utilized to produce biomass-based substitute natural gas (BioSNG) via syngas biomethanation. CO biomethanation is one of the key issues in the biomethanation process and was studied experimentally in this work with respect to the effect of anaerobic granular sludge semi-disaggregation. The results show 1.07 times higher averaged CH4 production rate with the semi-disaggregated granular sludge than the whole granular sludge at 35 °C, and 1.69 times higher at 55 °C. The main mechanisms behind the enhanced CH4 production rate, especially under the thermophilic condition, are the improvement of microbial interspecific syntrophic association caused by the higher electron and substrate transfer rate, and more active cell growth and metabolism as reflected in higher abundance of functional genes and enzymes and less useless extracellular polymeric substances. The CO biomethanation enhancement occurs in the conversion of the substrate to the intermediate products. The semi-disaggregation of anaerobic granular sludge or similar way to strengthen interspecific association is an effective approach to improve the ability and tolerance of microbial cultures under the CO atmosphere. This technique can well be applied for the energy conversion from the CO-rich gas substrates into BioSNG via CO biomethanation under the thermophilic condition, or for the production of intermediates as fuels/chemicals under the mesophilic condition. 

The pine sawfly Diprion jingyuanensis Xiao and Zhang (Hymenoptera: Diprionidae) is a serious pest of Pinus tabulaeformis Carr. in the Shanxi, Gansu, and Inner Mongolia provinces in P. R. China. The sex pheromone of D. jingyuanensis was shown to be the propionate ester of 3,7-dimethyl-2-tridecanol. Virgin females contained an approximate 1:3 blend of the pheromone precursors erythro-(2S,3S,7R/S and 2R,3R,7R/S)-3,7-dimethyl-2-tridecanol and threo-(2S,3R,7R/S and 2R,3S,7R/S)-3,7-dimethyl-2-tridecanol, but the exact stereoisomers were not determined. Males responded the strongest to the propionate ester of the two threo-isomers, (2S,3R,7R) and (2S,3R,7S), in electroantennogram (EAG) recordings, followed by a significant EAG response to the (2S,3R,7R) propionate of diprionol (pheromone component of D. similis), whereas the remaining two isomers (2S,3S,7S and 2S,3S,7R) of the propionate ester of 3,7-dimethyl-2-tridecanol and the acetate of the (2S,3R,7R) isomer (one of the two pheromone components of D. pini) did not elicit any significant increase in antennal response. In the field, the strongly EAG-active (2S,3R,7R)-isomer alone was only weakly (but significantly) attractive to D. jingyuanensis males at 100 µg, while the equally EAG- active (2S,3R,7S)-isomer alone at the same loading was 8–14 times more attractive than was the (2S,3R,7R)-isomer alone. Traps baited with the same amounts of the two threo-isomers ((2S,3R,7R) and (2S,3R,7S), 100 µg + 100 µg) caught significantly more males than did traps baited with other isomers, either of the two isomers alone or other proportions of the two isomers. Thus, the (2S,3R,7S)-isomer is considered as a strong and essential sex-attractant component for D. jingyuanensis males, whereas the (2S,3R,7R)-isomer is a weak but synergistic sex-attractant. This is one of the few examples of a pine sawfly responding significantly stronger to a binary blend of stereoisomers in a synergistic fashion than to a single stereoisomer alone.