Transformation of the water soluble fraction from “alpeorujo” by Coriolopsis rigida: The role of laccase in the process and its impact on Azospirillum brasiliense survival

Abstract

The objective of this work was to evaluate the ability of the white rot basidiomycete Coriolopsis rigida to detoxify the water soluble fraction from "alpeorujo" (WSFA), a solid by-product produced by the olive oil extraction industry and characterized by a high concentration of phenols which limits its use as fertilizer and/or amendment. C. rigida reduced the phenol content in the liquid media supplemented with WSFA at 10 and 20% (v/v) after 15d of incubation. The analysis of WSFA toxicity after fungal treatment showed that C. rigida was responsible for a significant increase in the survival rate of Azospirillum brasiliense, a N(2) fixing soil rhizobacterium which promotes plant growth. Supplementation of culture medium with CuSO(4) (300 microM) resulted in strong laccase induction thus facilitating higher phenol reduction and detoxification of WSFA. In vitro reactions using a crude extracellular preparation from laccase-active C. rigida showed phenol removal as well as detoxification of the WSFA at 20%. These results suggest that C. rigida reduces the phenol content of the WSFA through the effect of laccase on free phenolic compounds consequently decreasing the toxic effect on A. brasiliense, which suggests that the enzyme plays an important role in the process. These findings have implications in the management and revalorization of olive-mill residues treated with laccase-producing fungi and their potential impact on integrative agricultural systems including organic residues and the co-inoculation with microorganisms which can facilitate the growth of plants of agricultural interest.

The phytotoxicity of 2,4,6-Trichlorophenol and Phenol to local agricultural plant species in China

“…Larger the seed was, less sensitive was to the chemicals. Larger seed may correlate with their higher capability to neutralize the toxic chemicals, possibly via the various mechanisms of degrading the toxic chemicals [3,[15][16][17]. Although we did not observe a similar correlation in the studies with TCP, it could be due to the fact that TCP was much more toxic than phenol and so the differential tolerance of the seed could not be observed.…”

Bioremediation of dry olive-mill residue removes inhibition of growth induced by this waste in tomato plants

“…It is known that saprobe fungi possess extracellular laccase and peroxidase that can degrade phenolic compounds (Aranda et al 2006(Aranda et al , 2007Sampedro et al 2004;Saparrat et al 2010). Consistently, when plants were grown in the presence of ADOR bioremediated with P. chrsysogenum-10, the increase in phenolics in roots was appreciably reduced and only showed significant differences 4 days after treatment.…”

“…The ability of saprobe fungi to bioremediate DOR is due to the presence of extracellular enzymes, namely laccase and peroxidase (Aranda et al 2006(Aranda et al , 2007Sampedro et al 2004). It has been demonstrated that a relationship exists between the production of laccase by the saprobe fungus Coriolopsis rigida and degradation of phenolic compounds in aqueous extracts of DOR (ADOR) (Aranda et al 2006(Aranda et al , 2007Saparrat et al 2010). In addition, previous studies show that the production of hydrolytic enzymes by the saprobe fungus Penicillium chrysogenum-10 leads to a decrease in ADOR phytotoxicity .…”

“…Due to its high organic and inorganic nutrient content, DOR has great potential as fertilizer (Sampedro et al 2007a). However, DOR also contains phytotoxic compounds capable of inhibiting the growth of microorganisms and thus germination and growth of plants Saparrat et al 2010). Therefore, before being applied to agricultural soils as an organic fertilizer, DOR needs to be remediated.…”

Response of the fungus Pseudocercospora griseola f. mesoamericana to Tricyclazole

“…Then, the resultant suspension was centrifuged at 5,000 g for 5 min and the pellet was dried in an oven at 40°C overnight. Dry mycelium was embedded in infrared grade KBr disk (2 mg 20 mg −1 ) and recorded in a Perkin-Elmer-Instruments spectrometer (scanning range: 400-4,000 cm −1 , resolution: 4 cm −1 , number of scans: 64), the data of which was processed by means of the software OMNIC (Thermo Nicolet, Madison, WI) according to Saparrat et al (2010). This experiment was performed once with three replicates.…”