From samples of moldy wall paint and damaged water-based paint, we isolated and quantified the density of microorganisms present in the samples and determined the morphology of the isolates; thereby, identifying the genera of the bacteria and mold strains. The results showed that the density of the strains collected from the wall paint samples was much higher than that of the water-based paint samples (106 CFU/mL and 104 CFU/mL, respectively). In the wall paint samples, only mold colonies were observed, not bacterial colonies, while in the water-based paint samples both mold and bacterial colonies appeared, although mold colonies were still predominant. Based on the observation of colony formation and microscopic morphology of molds, we classified six mold strains into five genera: Aspergillus sp., Cladosporum sp., Acremoium sp., Chaetomium sp., and Fusarium sp. The frequency of strains belonging to the genus Aspergillus sp. accounted for the majority in both wall and water-based paint samples. Among the three bacterial strains isolated, we identified two bacterial strains as G (-) and one strain as G (+).

The study was conducted to evaluate the influence of arbuscular mycorrhizal fungus (Rhizophagus intradices) on growth and polyphenol production of the two important and popular medicinal plants in Vietnam: Ehretia asperula Zoll. & Mor. and Solanum procumbens Lour. The results showed a significant effect of the fungus on the growth of these two species with the growth indices such as height, weight and P content that were all higher than those of non-AM plants; although the indices of AM symbiosis in the plant roots were not as high as other plants in previous studies. The effect of AM fungus on polyphenol production was different between the two species. In E. asperula, the effect of AM fungi on polyphenol production was not significant; whereas in S. procumbens, AM symbiosis significantly increased polyphenol production in plant biomass, especially in roots. The different growth times of the two species might cause the different effects of AM fungus on polyphenol production.