A Comparative Study on Trichoderma harzianum and a Combination of Candida/Bacillus as Tools for the Bioremediation of Table Olive Processing Water

Abstract

A comparative study was performed on Trichoderma harzianum and a combination of Candida boidinii/Bacillus pumilus to reduce the polluting effect of TOPW (Table Olive Processing Water) from the Spanish style. A 2k fractional design was used to study the effect of pH (6–11 for the fungus and 6–9 for Candida/Bacillus), temperature (10–35 °C) and duration (7–14 days for Candida/Bacillus and 14–21 days for T. harzianum), and the effect on phenol reduction, COD and color was evaluated. The experiments were also performed on diluted TOPW (dilution ratio 1:1). Generally, Trichoderma removed higher amounts of phenols and reduced COD more than the combination Candida/Bacillus, thus confirming the higher efficiency of filamentous fungi reported in the literature. The dilution of TOPW had an effect only on COD reduction; however, the effect was mild, at least for T. harzianum (4%), while yield increase was 9% for Bacillus/Candida. pH acted in a different way on phenol removal and COD reduction; an increase of pH caused a reduction of efficiency for COD, while the effect was positive for phenols.

Removal of Phenols in Table Olive Processing Wastewater by Using a Mixed Inoculum of Candida boidinii and Bacillus pumilus: Effects of Inoculation Dynamics, Temperature, pH, and Effluent Age on the Abatement Efficiency

“…Bacillus pumilus 13M and Candida boidinii 682, were used in this study [ 10 ]. B. pumilus and C. boidinii were grown before each assay in Tryptone Soya broth at 30 °C for 48 h (Oxoid, Basingstoke, UK) and on YPG broth at 25 °C for 72 h (yeast extract, 10 g/L; peptone, 20 g/L; glucose, 20 g/L; Oxoid), respectively.…”

“…Several treatments have been proved to be fairly effective in reducing the environmental impact of these wastewater, for example advanced oxidation processes such us Ozonation, Fenton reaction [ 5 ], Electrochemical treatment, TiO 2 Photocatalysis, Electro-Coagulation, Wet Air Oxidation, but they are still too expensive or cannot always be applied at industrial level. Biological treatments, including aerobic and anaerobic processes according to the type of microorganisms and the presence or absence of oxygen, are considered as economical and effective alternative approaches [ 3 , 10 , 11 ].…”

“…Several studies report on the potentialities of some bacteria ( Bacillus , Pediococcus , Lactobacillus , Arthrobacter , Azotobacter , Pseudomonas and Ralstonia ) [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ] and fungi ( Candida tropicalis , Candida cylindracea , Yarrovia lypolitica , Phanerodontia chrysosporium , Trametes versicolor , Funalia trogii , Lentinus edodes , Aspergillus niger and Aspergillus terreus ) [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ] as bioremediation tools, although few data are available for TOPW. In the past, Campaniello et al [ 10 ] evaluated the effect of a combination of B. pumilus / C. boidinii and Trichoderma harzianum on TOPW and found significant levels of COD (4000 mg/L for T. harzianum and 2400 mg/L for C. boidinii / B. pumilus ) and phenol reduction (up to 1800 mg/L for the combination C. boidinii / B. pumilus and 2800 mg/L for T. harzianum ). In that research, some variables were not studied, e.g., the protocol for inoculation of Bacillus and Candida and the kind of TOPW with respect of their “age”.…”

Natural β-Carotene Production by Blakeslea trispora Cultivated in Spanish-Style Green Olive Processing Wastewaters

“…Although effluents storage in evaporation ponds is the main applied treatment so far, this approach involves several risks related to the contamination of the terrestrial ecosystem and the release of fetid gasses [ 20 ]. To address the above problem, several studies have been carried out toward the effective detoxification of the streams through the eco-friendly and inexpensive biological treatment with activated sludge, fungi ( Aspergillus niger , Geotrichum candidum , Trichoderma harzianum , white-rot fungi) or microalgae ( Nannochloropsis gaditana ) [ 20 , 23 , 24 ]. In recent investigations from our group [ 21 , 25 ], these effluents have been valorized for the microbial production of citric acid by A. niger with the integrated co-production of hydrolytic enzymes with higher commercial value.…”

Processing Wastewaters from Spanish-Style cv. Chalkidiki Green Olives: A Potential Source of Enterococcus casseliflavus and Hydroxytyrosol

“…The development of sustainable remediation processes is a tough challenge and bioaugmentation via the use of exogenous fungi (white-rot fungi, Aspergillus niger , Geotrichum candidum , Trichoderma harzianum ), microalgae ( Nannochloropsis gaditana ), or activated sludge has emerged as a feasible, green, and cost-effective approach. However, recent findings highlight the limited adaptability of these microbial cells to GOW and their limited ability to degrade the toxic organic constituents (i.e., phenolic compounds) [ 2 , 5 , 6 ]. A. niger has been recognized as metabolically superior against the other tested microorganisms in terms of phenol degradation and phytotoxicity reduction [ 3 ].…”