Design and testing of a cost-efficient bioremediation system for tannery effluents using native chromium-resistant filamentous fungi

In Arequipa (Peru), a small-scale tannery industry cannot afford costly or complicated methods for effluent treatment. In this work, we designed and tested a bubble column bioreactor for tannery effluent treatment based on the native filamentous fungi Penicillium citrinum and Trichoderma viride. The bioreactor construction used low-cost materials, with an easy-to-handle design. The parameters considered for testing were based on current Peruvian legislation. In the bioreactor, P. citrinum successfully reduced the effluent content of sulfides, chemical oxygen demand (COD) and total suspended solids (TSS) and removed nearly 80% of the chromium (VI) after 120 h of reaction. The resulting treated effluent had a composition within the maximum limits permitted by Peruvian legislation. Trichoderma viride also reduced the content of TSS, COD and sulfides, but decreased the chromium (VI) concentration by only ~ 20% after the same reaction time. Both filamentous fungi were able to grow in the experimental conditions used and the bioremediation process occurred with no significant alteration in pH. These findings indicate that a bubble column bioreactor using P. citrinum as a bioremediator agent provides low-cost, effective technology for treating effluent waste produced by artisanal and small-size tannery factories in the region of Arequipa1738253834This study was fnanced by UNSA-INVESTIGA (Grant No. IBA-0030-2017) and was part of an undergraduate dissertation by S.V.Z.-

Chromium (VI) bioremediation potential of filamentous fungi isolated from Peruvian tannery industry effluents

The tannery is an important trade in various Peruvian regions; however, tannery effluents are a serious local environmental threat due to its highly toxics components and lack of efficient treatment. The untreated effluents produced by tannery factories in Arequipa Rio Seco Industrial Park (PIRS) have formed a lake in the region nearby. In this work, we study the capability of filamentous fungi species found in this effluents lake with potential for chromium (VI) bioremediation. Fourteen species of filamentous fungi were isolated; only two species were identified Penicillium citrinum and Trichoderma viride, and third strain identified as Penicillium sp. The filamentous fungi showed that are fully tolerant to chromium (VI) concentrations up to 100 mg/L. These fungal strains showed significant growth in chromium (VI) concentrations up to 250 mg/L. Tolerant index (TI) analysis revealed that P. citrinum and T. viride began adaptation to chromium (IV) concentrations of 250 and 500 mg/L, after 6 and 12 days, respectively. When exposed to higher Cr (VI) concentrations (1000 mg/L), only T. viride was able to show growth (enhance phase). Interestingly, one of the significant responses from these fungal strains to increasing chromium (VI) concentrations was an increment in secreted laccase enzymes. Our results show tolerance and adaptation to elevated concentrations of chromium (VI) of these fungal strains suggesting their potential as effective agents for bioremediation of tannery effluents