Content area
Full Text
Bull Environ Contam Toxicol (2017) 98:400406 DOI 10.1007/s00128-016-1958-5
http://crossmark.crossref.org/dialog/?doi=10.1007/s00128-016-1958-5&domain=pdf
Web End = http://crossmark.crossref.org/dialog/?doi=10.1007/s00128-016-1958-5&domain=pdf
Web End = Optimization ofCulture Conditions forGrowth Associated withCr(VI) Removal byWickerhamomyces anomalus M10
PabloMarceloFernndez1 ElasLeonardoCruz1 SilvanaCarolinaViarta1 LucaInsCastellanosdeFigueroa1,2
Abstract Chromate-resistant microorganisms with the ability of reducing toxic Cr(VI) to less toxic Cr(III), are candidates for bioremediation. An alternative culture medium to reduce Cr(VI) using Wickerhamomyces anomalus M10 was optimized. Using the Plackett-Burman design, it was determined that sucrose, K2HPO4 and inoculum size had signicant eects on chromate removal (i.e., reduction) at 24h. Concentrations of these signicant factors were adjusted using a complete factorial design. In this case, only the K2HPO4 eect was signicant at 12 h of culture, with greater Cr(VI) removal at low concentration (1.2 g L1). The optimum medium was validated at the fermenter scale level. Optimal culture conditions for complete removal of Cr(VI) (1mM) were 400rpm agitation and air ow of 1vvm. Moreover, W. anomalus M10 completely removed consecutively added pulses of Cr(VI) (1mM). These results show interesting characteristics from the standpoint of biotechnology because the development of a future remediation process using W. anomalus M10 can represent an efficient and highly protable technology for removing the toxic form of Cr.
Keywords Cr(VI) Bioremediation Cr(VI)-resistant yeasts Plackett-Burman Factorial design Bioreactor
Received: 17 February 2016 / Accepted: 18 October 2016 / Published online: 10 November 2016 Springer Science+Business Media New York 2016
Chromium (Cr) is a naturally occurring element found in rocks, animals, plants, soil, volcanic dust and gases, but the largest contribution to the deposition of Cr is the result of anthropogenic activities. Chromium is utilized in various industrial activities, including electroplating, steel, wood treatment, leather tanning, pigments, dyes and paints (Alam and Ahmad 2012; Lu etal. 2013).
Cr(VI) compounds are known to be extremely toxic to living organisms, causing allergies, irritations and respiratory tract disorders (Poljsak et al. 2010). Along with the strong oxidizing nature of Cr(VI), the intracellular reduction to Cr(III) gives rise to reactions with nucleic acids and other cell components in biological systems with consequent alterations of DNA and toxic eects (Poljsak et al. 2010; Zhitkovich 2011). On the other hand, Cr(III) at low concentrations constitutes an essential micronutrient for many higher organisms, being related to carbohydrate metabolism, synthesis and conformational stability of proteins and nucleic...