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Biodeterioration is a significant problem in the conservation of stone heritage buildings. In this study, 10 plant essential oils were assessed for their effectiveness in biofilm inhibition on stone heritage building surfaces under laboratory and in situ conditions, and were compared with traditional biocides such as benzalkonium chloride. The plant extracts were tested against algae and mosses. The effect on algae removal was evaluated by measuring the color of the surface before treatment, after 24 h and after 1 month of treatment. The effect on mosses was assessed by measuring the photosynthetic pigment content of mosses after 24 h of treatment. The results showed that the different plant extracts exhibited different levels of antibiotic activity. Benzalkonium chloride, S. aromaticum and C. cassia extracts showed strong antibiotic activity against all algae and mosses tested. T. mongolicus extracts showed antibiotic activity against only some of the algae and mosses, while the application of P. cablin extracts increased chlorophyll b content in the mosses. The other plant extracts were less effective at inhibiting the growth of algae and mosses. GC–MS compositional analysis further indicated that the higher antibiotic activity of S. aromaticum and C. cassia extracts was related to the high content of eugenol and cinnamaldehyde. [ABSTRACT FROM AUTHOR]

Background and aims: Karst rocky desertification (KRD), a land degradation form which is widespread but unique to karst ecosystems, has become an ecological disaster in southwest China. Biocrusts play crucial roles in many ecological processes of the degraded ecosystems. However, little is known about the effects of biocrusts on soil properties and soil microbial communities in the progression of KRD. Methods: We sampled soil beneath moss biocrusts and bare soil in four grades of KRD (none, light, moderate, and severe) to compare soil nutrients, soil microbial diversity, community composition, structure, and networks across the range of KRD progression. Results: Moss biocrusts had a positive effect on all soil nutrients and buffered the negative effects of KRD progression compared to bare soil. Moss biocrusts significantly increased soil microbial richness but had little contribution to diversity and community composition. Both soil bacterial and fungal communities were significantly correlated with total and available phosphorus, total potassium, soil temperature, slope, and altitude. Soil bacterial and fungal communities showed different sensitivities and strategies in face of environmental degradation in KRD-affected ecosystems. Conclusions: Moss biocrust restoration could be used as a supplementary method in promoting ecological restoration in areas undergoing KRD due to their positive effects on soil nutrients and soil microbial richness. Our findings filled a knowledge gap pertaining to the microbial ecology of biocrust in regions experiencing KRD. [ABSTRACT FROM AUTHOR]

The study aimed at investigating copper, lead, and cadmium removal from both single and mixed metal solutions by Michelia figo (Lour.) Spreng. wood sawdust treated with 0.5 mol l−1 NaOH for four hours. In order to evaluate the effects of each factor and interactions between factors on metal ion biosorption, a 23 factorial experimental design was applied. FTIR results showed that the metal ions would bind to the hydroxyl and carboxyl groups of M. figo wood sawdust biomass. The main effects and interactions of three factors pH (3 and 5), initial metal ion concentration (C0, 0.157 and 1.574 mmol L−1), and dosage of biomass (D, 4 and 10 g L−1) at two levels were analyzed. The most significant variable regarding Cu2+ and Pb2+ biosorption was initial metal iron concentration. For Cd2+, pH was found to be the most significant factor. The maximum removal efficiencies were 94.12 and 100% for Cu2+ and Cd2+, respectively, at conditions of (+ 1, − 1, + 1): pH 5, initial metal concentration 0.157 mmol L−1 and dosage of biomass 10 g L−1, while 96.39% for Pb2+ at conditions of (− 1, − 1, + 1): pH 3, initial metal concentration 0.157 mmol L−1 and dosage of biomass 10 g L−1. There were some interactions between factors: pH*C0 and C0*D for Cu2+, pH*C0, pH*D and C0*D for Pb2+, pH*C0 and C0*D for Cd2+. Biosorption from a multi metal system showed that the presence of Cu2+ and Cd2+ had no significant influence on the Pb2+ removal, while Pb2+ in solution significantly decreased the removal efficiencies of the other two metals. [ABSTRACT FROM AUTHOR]