Increase in lipid portion of Phycomyces blakesleeanus biomass induced by vanadate uptake and accumulation

Abstract

Fungi are ubiquitous micro-organisms involved in various environmental processes, with a particularly important role in the transformation of metals and minerals, bioremediation and biomining. Filamentous fungus Phycomyces blakesleeanus is an interesting model for investigating the interaction of fungi with various ecological factors, such as heavy metals, due to the ease of its cultivation and fast growth. The present study deals with the interaction of increasing vanadate [V(V)] concentrations with the mycelium of P. blakesleeanus in three distinct growth phases: mid-exponential, late exponential and stationary phase. Mid- and late-exponential phase mycelium had a V content of nearly 1% after 24 h incubation with 10 mM V(V), and the uptake of V(V) was accompanied by increased phosphorus uptake with both 5 and 10 mM V(V). Fourier Transform Infrared spectroscopy showed the increase of lipid portion in biomass compared to proteins and carbohydrates mainly with ageing, but also with vanadate treatment. P. blakesleeanus is tolerant to high V(V) concentrations, and this study suggests its potential as V accumulator. In addition, the increase in lipid content calls for a closer examination of lipid content and fatty acid composition after V(V) treatment and determination of their potential industrial utilization.