The collapse of agricultural infrastructure in Kazakhstan and other countries worldwide has resulted in the transfer of ownership or abandonment of plant protection chemicals storage facilities. Despite legislative measures and international conventions, the issue of persistent organic pollutants (POPs) remains unresolved. Measures to restore POP-pesticide-contaminated areas present limited options. Hence phytotechnology emerges as a promising strategy due to eco-friendliness and the absence of significant capital investments. One of the key aspects of technology is the search for novel plant species capable of accumulating and transforming these contaminants into less toxic compounds. Current study investigated the potential of the energy crop Miscanthus sinensis Anderson (M. sinensis) as a novel phyto plant for remediating POP-pesticide-contaminated soils. The experimental layout comprised cultivation of M. sinensis in POP-pesticide-contaminated (2.4-DDD, 4.4-DDD, 4.4-DDE, 4.4-DDT, α-HCH, β-HCH, γ-HCH, and δ-HCH) soil. Biomass productivity, physiological parameters, and phytoremediation potential were assessed at harvest. Our findings revealed that POP-pesticides influenced productive and physiological parameters of M. sinensis differently, specifically: reduced aboveground biomass and chlorophyll pigments content by up to 23 and 37%, respectively, and increased root biomass by up to 17%. Furthermore, the plant exhibited a remarkable tolerance to severe POP-pesticide contamination, as evidenced by a tolerance index of 0.99. Evaluation of phytoremediation coefficients revealed that M. sinensis employed distinct strategies depending on POP-pesticide: phytoextraction and phytostabilisation. 4.4-DDT, β-HCH, and γ-HCH were accumulated in aboveground biomass with translocation factors of 1.18, 4.04, and 84.0, respectively. Whereas metabolite 4.4-DDE was accumulated in plant roots with a bioconcentration factor of 2.07. Study results suggest that M. sinensis holds great promise for use in POP-pesticides phytoremediation projects, particularly in Kazakhstan, owing to confirmed phytostabilisation activity concerning 4.4-DDE, the final metabolite of 4.4-DDT degradation. Therefore, further research should focus on optimizing M. sinensis phytostabilisation strategies for other POP-pesticides.

The need for the increasing geographical spread of fire blight (FB) affecting fruit crops to be addressed led to large-scale chemicalization of the environmental matrices and reduction of plant productivity. The current study aimed to assess the effects of novel biopreparations at different exposure durations on photosynthetic pigment content and antioxidant enzyme activity in leaves of apple and pear varieties with varying levels of resistance to FB. Biopreparations were formulated from a cultural broth containing Lacticaseibacillus paracasei M12 or Bacillus amyloliquefaciens MB40 isolated from apple trees’ phyllosphere. Aseptic leaves from blight-resistant (endemic Malus sieversii cv. KG10), moderately resistant (Pyrus pyraster cv. Wild), and susceptible (endangered Malus domestica cv. Aport and Pyrus communis cv. Shygys) varieties were employed. The impact of biopreparations on fruit crop antioxidant systems and photosynthetic apparatuses was investigated in vitro. Study results indicated that FB-resistant varieties exhibit enhanced adaptability and oxidative stress resistance compared to susceptible ones. Plant response to biopreparations varied based on the plant’s initial FB sensitivity and exposure duration. Indeed, biopreparations improved the adaptive response of the assimilation apparatus, protein synthesis, and catalase and superoxide dismutase activity in susceptible varieties, suggesting that biopreparations have the potential for future commercialization to manage FB in fruit crops.

Environmental contamination by potentially toxic elements (PTEs) originating from industrial activities represents a major global challenge, necessitating the development of sustainable remediation strategies. While remediation of legacy (post-industrial) contamination has been relatively well studied, the remediation of ecosystems surrounding operating facilities subjected to increasing PTE loads remains insufficiently investigated. Therefore, the present study evaluated the efficacy of biochar derived from post-phytoremediation Miscanthus × giganteus (M×g) biomass to optimise the phytoremediation process using soil from an operating facility in a pot system. Valorisation of 29.0 kg of waste biomass yielded 12.8 kg of biochar (44.2%) with a high specific surface area (672 m² g⁻¹). Despite PTE enrichment during pyrolysis, the biochar was classified safe according to IBI thresholds. A pot experiment was conducted using contaminated and local background soils, amended with 3% (w/w) Miscanthus-derived biochar. Biochar application significantly improved plant performance in contaminated soil, increasing plant height, aboveground biomass, and root parameters by up to 208%, while restoring chlorophyll content and reducing stress indicators such as proline. Furthermore, biochar reduced PTE accumulation in plant tissues and supported the production of less contaminated biomass. These findings demonstrate that post-phytoremediation biomass-derived biochar enhances phytomanagement efficiency and supports sustainable biomass valorisation within a circular economy framework.

В данном обзоре были рассмотрены вопросы применения биочара в качестве удобрения и носителя интродуцируемых микроорганизмов для решения задач экологической биотехнологии. Более того в обзоре описаны методы получения биочара с заданными физико-химическими свойствами, механизмы его взаимодействия с органическими (пестицидами) и неорганическими (тяжёлыми металлами) загрязнителями, а также потенциальные риски, связанные с его использованием. Особое внимание было уделено механизмам иммобилизации микробных клеток на поверхности биочара, их взаимодействию с углеродной матрицей и возможностям применения таких композиций для очистки почв от загрязнителей. В обзоре обобщены и углублены знания об использовании микроорганизмов, иммобилизованных на биочаре, для восстановления структурных характеристик почвы и повышения её плодородия. Повышение эффективности фиторемедиация является стратегически важным этапом исследований. С целью ускорения наращивания биомассы растений, повышения эффективности технологии очистки и адаптивности растений, биочар рассматривается в качестве внедряемого инструмента для усиления технологий био– и фиторемедиации. Биочар получали путём термического разложения растительных или животных остатков в анаэробных условиях или при пониженном содержании кислорода. Положительное влияние биочара на свойства почвы и рост растений объяснялось наличием в его составе минералов (K, Ca, P, Na, Mg и др.), способствующих нейтрализации кислотности, снижению абиотического стресса и стимуляции роста растений. Кроме того, биочар адсорбировал токсичные элементы, что приводило к снижению их мобильности, биодоступности и фито- и экотоксичности. Практическое применение биочара было представлено как инновационный подход к минимизации загрязнения почв. Целью статьи является расширение представлений о современных методах иммобилизации микроорганизмов на биочаре для улучшения почвенных свойств, повышения плодородия и эффективной стабилизации органических и неорганических загрязнителей в окружающей среде.

RECHAR-M2C: MICROBIAL ISOLATION FROM LEGACY-CONTAMINATED SOILS The present study aimed to isolate Zn-solubilising and metal-tolerant microbial strains from legacy-contaminated soils affected by potentially toxic elements (PTEs), persistent organic pollutants (POPs), or their combination. A total of 242 microbial strains were isolated. Subsequent sequential screening for Zn-solubilisation potential identified 13 isolates with solubilisation indices exceeding 1.5. Of these, four isolates (S21, S56, TA5, and TE32) exhibited strong tolerance to 0.03–0.06% Zn, with relative growth intensities (RGIs) ranging from 86.6% to 104%, while S56 and TE32 maintained sufficient tolerance at a Zn concentration of 0.12%. Regarding Ni tolerance, only TE32 exhibited sufficient resistance at a Ni concentration of 0.03%, with an RGI of 47.2%. For Cu tolerance, isolates S21, S56, and TE32 demonstrated strong resistance at a Cu concentration of 0.03%, with RGIs of 92.8%, 82.4%, and 79.6%, respectively. Furthermore, TE32 maintained sufficient tolerance at 0.06% Cu, with an RGI of 63.0%. Based on these results, three isolates (S21, S56, and TE32) were selected for comprehensive characterisation of their enzymatic (amylolytic, cellulolytic, lipolytic, and proteolytic) and plant growth-promoting traits, including siderophore, extracellular polymeric saccharide (EPS), and indole-3-acetic acid (IAA) production. Strain S21 exhibited moderate proteolytic activity, siderophore production, and superior IAA synthesis, reaching a peak concentration of 38.7 ± 3.29 µg mL−1. Strain S56 demonstrated moderate proteolytic activity, strong lipolytic and proteolytic activities, siderophore production, and moderate IAA synthesis, with a maximum concentration of 17.5 ± 1.48 µg mL−1. In contrast, strain TE32 exhibited strong amylolytic activity, proteolytic activity, EPS production, and the lowest IAA-producing capacity, reaching a peak concentration of 12.8 ± 0.88 µg mL−1. Future research will focus on the development of microbe–biochar complexes through the immobilisation of microbial cells onto biochar surfaces, followed by validation of the developed complexes in marginal and/or contaminated soils to enhance plant growth. Keywords: legacy soil contamination; potentially toxic elements; Zn-solubilising microorganisms; tolerance to heavy metals; plant growth-promoting microorganisms.