Optimization of the Fermentation Conditions for Brewing Yeast Biomass Production Using the Response Surface Methodology and Taguchi Technique

Yeast (including brewing yeast) and yeast-based preparations derived from bioprocesses or agroindustrial byproducts represent valuable feed additives and ingredients for ruminants. The optimization of brewing yeast biotechnological processing through fermentation mediated by the brewing yeast strain Saccharomyces pastorianus ssp. carlsbergensis W34/70 was investigated. The cultivation conditions (temperature, pH, carbon source, and nitrogen source) were selected and designed according to a Taguchi fractional experimental plan, with four factors on three levels, and their influence on the evolution of the bioprocess of obtaining the brewing yeast biomass was evaluated. The dependent variables were the yeast biomass amount in wet form, yeast biomass amount in dried form after lyophilization, dried yeast biomass wettability assayed through the contact angle (CA), protein content (PC), and dry matter content (DS). The effects that the experimental conditions had on the system responses were visualized in tridimensional space using the response surface methodology, and the combination of biotechnological parameters that ensured process quality and robustness was then determined using the Taguchi technique through its performance indicator, i.e., the signal-to-noise ratio. By optimizing the biotechnological parameters, this study provides a valuable contribution in the area of brewing yeast biomass processing, with the aim of producing probiotic yeast for ruminant nutrition.

A Preliminary Investigation of Marine Yeast Biodiversity in New Zealand Waters

<p>This is the first known investigation of marine yeast biodiversity from waters surrounding New Zealand’s main Islands. Marine yeasts were cultured onto agar plates from algae sampled at three locations in the Wellington Region. DNA extractions and PCR amplifications of the internal transcribed spacer (ITS) regions were conducted, and resultant sequence data were used for isolate identification and phylogenetic analysis. Yeasts isolated during this investigation were not unique; seventy-four isolates were identified from a range of genera that are frequently detected in marine and terrestrial environments worldwide. Furthermore, high ITS sequence similarity was observed between yeasts isolated during this investigation and those from geographically distant locations. These findings may indicate that marine yeasts are ubiquitous at a global level, although evidence is insufficient as to whether yeasts also demonstrate biogeographic distribution patterns. Yeasts isolated during this investigation may have ecological implications in New Zealand’s marine environment; marine yeasts are likely to play a general saprophytic role and certain genera are pathogenic. Isolates were also identified from genera that have previously demonstrated beneficial properties and applications, including the production of useful compounds and highly nutritious yeast biomass, biocontrol potential against the postharvest decay of produce, and degradation abilities that may enable bioremediation of polluted marine environments.</p>

A Preliminary Investigation of Marine Yeast Biodiversity in New Zealand Waters

<p>This is the first known investigation of marine yeast biodiversity from waters surrounding New Zealand’s main Islands. Marine yeasts were cultured onto agar plates from algae sampled at three locations in the Wellington Region. DNA extractions and PCR amplifications of the internal transcribed spacer (ITS) regions were conducted, and resultant sequence data were used for isolate identification and phylogenetic analysis. Yeasts isolated during this investigation were not unique; seventy-four isolates were identified from a range of genera that are frequently detected in marine and terrestrial environments worldwide. Furthermore, high ITS sequence similarity was observed between yeasts isolated during this investigation and those from geographically distant locations. These findings may indicate that marine yeasts are ubiquitous at a global level, although evidence is insufficient as to whether yeasts also demonstrate biogeographic distribution patterns. Yeasts isolated during this investigation may have ecological implications in New Zealand’s marine environment; marine yeasts are likely to play a general saprophytic role and certain genera are pathogenic. Isolates were also identified from genera that have previously demonstrated beneficial properties and applications, including the production of useful compounds and highly nutritious yeast biomass, biocontrol potential against the postharvest decay of produce, and degradation abilities that may enable bioremediation of polluted marine environments.</p>

PSIII-4 Nutritional evaluation of yeast biomass from candida utilis as a protein source in cat diets

Yeast products have found much favor within companion animal nutrition. A recently developed proprietary process has introduced an enhanced yeast biomass from Candida utilis (merchandised as SylPro®) into the animal food marketplace. Candida utilis has been shown to be a valuable protein in canine, swine and aquaculture diets; however, no previous research has evaluated its use in feline diets. Therefore, the current objective was to determine the nutrient digestibility of diets containing SylPro® yeast biomass (SYL) as the primary protein source relative to soybean meal (SOY), pea protein concentrate (PEA), and chicken meal (CKN) fed to cats. Apparent total tract digestibility (ATTD) of diets were estimated using Titanium dioxide as an indigestible marker. The DM ATTD for SYL was lower (P &lt; 0.0001) than CKN (86.39 vs. 87.43%, respectively) but similar to both SOY (85.66%) and PEA (86.54%). The OM ATTD of SYL, SOY, and PEA were not different (P &lt; 0.0001) and were each lower than CKN (average of 89.60 vs. 91.16%, respectively). The CP ATTD for SYL (89.9%) was not different from the other three treatments (P = 0.0200). Crude fat ATTD of SYL was lower (92.52%; P &lt; 0.0001) than all treatments with PEA being greatest (94.82%) and CKN and SOY intermediate (average of 93.84%). The SYL and CKN had higher TDF ATTD (average of 66.20%; P &lt; 0.0001) relative to PEA and SOY (average of 49.79%). The GE ATTD of SYL was lower than CKN (90.18 vs. 90.97%, respectively; P = 0.0154) but similar to both SOY (90.18%) and PEA (90.30%). In conclusion, all diets were highly digestible but CKN preformed the best. The SYL diet was similar to CKN for ATTD of CP and TDF. The SYL diet was also similar to both SOY and PEA for ATTD of DM, OM, CP and GE.

Comparative analysis of L-carnitine production by Yarrowia lipolytica in different culture conditions in biofuel waste and fatty acid-poor medium for commercial purposes

Background Yarrowia lipolytica is an oleaginous yeast with the ability to grow in a variety of hydrophilic and hydrophobic substrates, including industrial wastes, in which it produces and accumulates various nutrients. Methods The aim of the present study was to examine the presence of free L-carnitine in the biomasses of two Yarrowia lipolytica strains (A-101 and ATCC 9793) growing in biofuel waste and YPD medium. The cultivations of Y. lipolytica were performed in aerobic conditions at different temperatures (20–30°C) and pH values (4.0–7.0) of the media with and without the addition of precursors for L-carnitine production (trimethyllysine, iron, and L-ascorbic acid) in a laboratory scale or other substances (chromium, selenite, or zinc) in a pilot plant scale. Results Both tested Y. lipolytica strains grown in fatty acid-poor YPD medium contained endogenous free L-carnitine in their biomass with a maximum of 22.85 mg/100 g of wet biomass. The addition of L-carnitine precursors to the YPD medium exerted a significant effect on L-carnitine concentration in the yeast biomass, increasing it up to 250%. In turn, the biomass of both tested Y. lipolytica strains cultivated in the biofuel waste, irrespective of the culture conditions, contained below 1 mg of L-carnitine/100 g of wet biomass. However, the supplementation of the culture media with the L-carnitine precursors significantly increased the yield of the yeast biomass by 20–30% in the non-fermentable biofuel waste cultures. Moreover, the addition of chromium (III) chloride into the biofuel waste caused an increase in the free L-carnitine concentration in the yeast biomass up to 2.24 mg/100 g of dry weight. Conclusion Biomass of Y. lipolytica grown in the fat-poor medium contained free L-carnitine, in contrast to the biomass grown in the fat-rich biofuel waste. The very low amounts of L-carnitine in the biomass of Y. lipolytica grown in the crude biofuel waste suggest that the yeast is able to utilize almost the entire pool of free L-carnitine for growth and nutritional biomass production. However, the addition of chromium to the biofuel waste contributed to an increase in L-carnitine concentration in Y. lipolytica biomass.

Yacon as a culture medium constituent to culture yeasts

Авторами установлено, что корнеклубни якона могут использоваться эффективно в качестве компонента питательной среды для культивирования дрожжей. Выявлено, что добавление мальтозы в питательную среду с яконом не оказывает существенного влияния на накопление биомассы дрожжей Rhodotorula glutinis ВКПМ Y-3469 и Pichia kluyveri ВКПМ Y-4343 селекции НИИ биотехнологии Горского ГАУ. The authors found that yacon pips can be effectively used as a culture medium constituent to cultivate yeasts. It was found that the maltose supplements to the culture medium with yacon do not significantly affect the accumulation of yeast biomass Rhodotorula glutinis VKPM Y-3469, Pichia kluyveri VKPM Y-4343 selected by the Research Institute of Biotechnology, Gorsky State Agrarian University.

Production of Enriched Sporidiobolus sp. Yeast Biomass Cultivated on Mixed Coffee Hydrolyzate and Fat/Oil Waste Materials

One of the most addressed topics today is the transfer from a linear model of economics to a model of circular economics. It is a discipline that seeks to eliminate waste produced by various industries. The food industry generates huge amounts of waste worldwide, particularly the coffee industry, and related industries produce millions of tons of waste a year. These wastes have potential utility in biotechnology, and in the production of energy, fuels, fertilizers and nutrients, using green techniques such as anaerobic digestion, co-digestion, composting, enzymatic action, and ultrasonic and hydrothermal carbonization. This work is focused on the biotechnological use of processed spent coffee grounds (SCG) and waste fat/oil materials by some Sporidiobolus sp. carotenogenic yeasts in the model of circular economics. The results show that selected yeast strains are able to grow on SCG hydrolysate and are resistant to antimicrobial compounds present in media. The most productive strain Sporidiobolus pararoseus CCY19-9-6 was chosen for bioreactor cultivation in media with a mixture of coffee lignocellulose fraction and some fat wastes. Sporidiobolus pararoseus CCY19-9-6 was able to produce more than 22 g/L of biomass in mixture of SCG hydrolysate and both coffee oil and frying oil. The combined waste substrates induced the production of lipidic metabolites, whereby the production of carotenoids exceeded 5 mg/g of dry biomass. On media with coffee oil, this strain produced high amounts of ubiquinone (8.265 ± 1.648 mg/g) and ergosterol (13.485 ± 1.275 mg/g). Overall, the results prove that a combination of waste substrates is a promising option for the production of carotenoid- and lipid-enriched yeast biomass.