Biosynthesis of single-cell biomass from olive mill wastewater by newly isolated yeasts

Abstract

The aim of this study was to assess the potential of newly isolated yeast strains Schwanniomyces etchellsii M2 and Candida pararugosa BM24 to produce yeast biomass on olive mill wastewater (OMW). Maximum biomass yield was obtained at 75% (v/v) OMW, after 96 h of incubation at 30 °C and 5% (v/v) inoculum size. The optimal carbon/nitrogen (C/N) ratio was in the range of 8:1 to 10:1, and ammonium chloride was selected as the most suitable nitrogen source. Under these conditions, a maximum biomass production of 15.11 and 21.68 g L(-1) was achieved for Schwanniomyces etchellsii M2 and Candida pararugosa BM24, respectively. Proteins were the major constituents of yeast cells (35.9-39.4% dry weight), lipids were 2.8-5% dry weight, and ash ranged from 4.8 to 9.5 % dry weight. Besides biomass production, yeast strains were also able to reduce toxicity and polluting parameter levels of the spent OMW-based medium. The practical results presented show that pH rose from initial value of 5.5 to 7.24-7.45 after fermentation. Approximately 23.1-41.4% of the chemical oxygen demand (COD) and 15.4-19.2% of the phenolic compounds were removed. The removal of phenolic compounds was associated with their biodegradation and their partial adsorption on yeast cells.

Fungal Biomass Protein Production fromTrichoderma harzianumUsing Rice Polishing

“…Agroindustrial wastes are reported extensively for the production of SCP [23, 24]. Here we showed that rice polishing was much more effective in increased crude protein and cell mass production.…”

Improved Production of Kynurenic Acid by Yarrowia lipolytica in Media Containing Different Honeys

“…These cultures showed also the highest determined KYNA amount. It should be pointed out that protein content and amino acid profile are strongly dependent on the carbon source, the composition of the culture medium, culture conditions (e.g., cultivation time) the growth phase and used microorganism [22,23]. However, in the present study, the used yeast strain and conditions of all the cultures were the same, so the obtained differences are the results of the composition of the medium (type of honey or presence of fructose).…”

“…Since the dry yeast biomass could potentially serve as a diet supplement, the biological value of the produced yeast protein was analyzed. Yeast biomass can provide valuable and alternative sources of protein exhibiting a nutritional value comparable to protein of animal origin [22][23][24]. In the analyzed yeast biomass, all essential amino acids were compared to the standard-whole egg protein (FAO/WHO standard) (Table 4).…”

Processing, Valorization and Application of Bio-Waste Derived Compounds from Potato, Tomato, Olive and Cereals: A Review

“…Aouidi, et al [419] studied the production of Geotrichum candidum biomass, for its use as starter for cheese production using a combination of OMW enriched with cheese whey and found that the combination was a cost effective medium. OMW is also a good source of nutrients for the production of microbial protein from new isolated yeasts, e.g., Schwanniomyces etchellsiii M2 and Candida pararugosa BM24 [420].…”