Bioremoval of toxic substances in synthetic wastewater using Trichoderma pubescens (NPK2), isolated from mangrove soil

Survey of organochlorine-tolerant culturable mycota from contaminated soils, and 2,4-D removal ability of Penicillium species in synthetic wastewater

Agrochemical wastewater, which is produced by the extensive use of herbicides, has become a serious environmental pollutant. In this study, culturable mycota were isolated from soils contaminated with herbicides 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chloro-2-methylphenoxyacetic acid (MCPA), and their ability to tolerate and remove 2,4-D was assessed. The mycota were isolated on solid medium supplemented with 10 mmol L^-1 of MCPA or 2,4-D. Tolerance and removal assays were performed in synthetic wastewater, and removal was quantified by HPLC-UV and MS/MS. Fusarium spp., Aspergillus spp., and Penicillium spp. were the most frequently isolated genera. Six Penicillium strains were able to tolerate up to 25 mmol L^-1 of 2,4-D. Within this group, two P. crustosum strains (RCP4 and RCP13) degraded more than 50% of the 2,4-D in the medium during the first 7 days of incubation. Removal percentages reached 54% for RCP4 and 75% for RCP13 after 14 days. These two strains, therefore, could potentially be considered for the design of bioaugmentation strategies aimed at reducing contamination by 2,4-D in wastewater.

Soil Type Affects Organic Acid Production and Phosphorus Solubilization Efficiency Mediated by Several Native Fungal Strains from Mexico

Phosphorus (P) is considered a scarce macronutrient for plants in most tropical soils. The application of rock phosphate (RP) has been used to fertilize crops, but the amount of P released is not always at a necessary level for the plant. An alternative to this problem is the use of Phosphorus Solubilizing Microorganisms (PSM) to release P from chemically unavailable forms. This study compared the P sorption capacity of soils (the ability to retain P, making it unavailable for the plant) and the profile of organic acids (OA) produced by fungal isolates and the in vitro solubilization efficiency of RP. Trichoderma and Aspergillus strains were assessed in media with or without RP and different soils (Andisol, Alfisol, Vertisol). The type and amount of OA and the amount of soluble P were quantified, and according to our data, under the conditions tested, significant differences were observed in the OA profiles and the amount of soluble P present in the different soils. The efficiency to solubilize RP lies in the release of OAs with low acidity constants independent of the concentration at which they are released. It is proposed that the main mechanism of RP dissolution is the production of OAs.