Publications by authors named "Deniz Cekmecelioglu"

Fungal cellulases are the most sought-after biological molecules produced from microbial sources in the last four decades. Owing to their emerging applications in the bioenergy industry for hydrolyzing cellulose, for which they are the most abundant source on this planet, research trends are shifting heavily toward adapting to submerged fermentation. However, filamentous fungal species, which are efficient cellulase producers, are well-adapted to low-moisture solid support as the substrate, such as in nature.

View Article and Find Full Text PDF

The purpose of this study is to evaluate the effect of high hydrostatic pressure (HHP) as a novel approach for yeast cell disruption and lipid extraction from Lipomyces starkeyi DSM 70295 grown in glucose medium (40 g/L and C/N:55/1) at initial pH of 5.0, 25°C, and 130 rpm for 8 days. HHP extraction conditions including pressure, time, and temperature were optimized by response surface methodology.

View Article and Find Full Text PDF

Distillers' dried grains with solubles (DDGS) is a by-product of dry-mill corn ethanol production comprising a high nutritional value due to residual fiber, protein, and lipid contents. The fiber content of DDGS is high enough to be considered a valuable source for the production of hydrolytic enzymes, such as cellulase and xylanases, which can be used for hydrolysis of lignocellulosic feedstock during ethanol production. The DDGS-based medium prepared after acid hydrolysis provides adequate sugars for enzyme production, while additional macronutrients, such as salts and nitrogen sources, can enhance the enzyme production.

View Article and Find Full Text PDF

Distillers' dried grain with solubles (DDGS) is a byproduct of bioethanol fermentation, which uses the dry milling technology for starch-rich grains such as corn, wheat, and barley. The current interest in bioethanol is increasing due to the need for renewable liquid fuels specifically in the transportation sector. Since DDGS is rich in crude protein, fat, fiber, vitamins, and minerals, it is currently used as aquaculture, livestock, and poultry feeds.

View Article and Find Full Text PDF

Distillers' dried grains with solubles (DDGS) is the by-product of bioethanol production from starch-rich grains through dry-mill fermentation. In this study, dilute sulfuric acid hydrolysis, aqueous ammonia, and steam explosion as the pre-treatment methods were optimized. The central composite response surface methodology (RSM) design was used for optimization of dilute acid pretreatment, aqueous ammonia pretreatment.

View Article and Find Full Text PDF

Co-cultures of and were investigated in submerged fermentation for xylanase production at shake-flask scale. Xylanase production markedly increased when arabinose, xylose, or hazelnut shells were used as the single carbon source. Maximal xylanase of 49.

View Article and Find Full Text PDF

Direct disposal of vinasse, a by-product of molasses fermentation plants, threatens environmental health. This study investigated the usage of vinasse as a nutrient source for the heterotrophic and mixotrophic cultivation of novel Micractinium sp. ME05.

View Article and Find Full Text PDF

It is well known that use of low cost and abundant waste materials in microbial fermentations can reduce product costs. Kitchen wastes disposed of in large amounts from cafeterias, restaurants, dining halls, food processing plants, and household kitchens contain high amounts of carbohydrate components such as glucose, starch, and cellulose. Efficient utilization of these sugars is another opportunity to reduce ethanol costs.

View Article and Find Full Text PDF

Using Response Surface Methodology, carbon and nitrogen sources and agitation speed for cultivation of Aspergillus sojae expressing the α-galactosidase gene, aglB of Aspergillus fumigatus IMI 385708 were optimized. Compared to cultivation in modified YpSs medium, cultivation in 250-mL Erlenmeyer flasks agitated at 276 rpm and containing 100 mL of optimized medium consisting of 10.5% molasses (w/v) and 1.

View Article and Find Full Text PDF

Food wastes disposed from residential and industrial kitchens have gained attention as a substrate in microbial fermentations to reduce product costs. In this study, the potential of simultaneously hydrolyzing and subsequently fermenting the mixed carbohydrate components of kitchen wastes were assessed and the effects of solid load, inoculum volume of baker's yeast, and fermentation time on ethanol production were evaluated by response surface methodology (RSM). The enzymatic hydrolysis process was complete within 6h.

View Article and Find Full Text PDF

An optimum composting recipe was investigated to reduce pathogenic microorganisms in a forced-aerated in-vessel system (55 liters). The feedstocks used for in-vessel composting were food waste, cow manure, and bulking materials (wood shavings and mulch hay). A statistical extreme vertices mixture design method was used to design the composting experiments and analyze the collected data.

View Article and Find Full Text PDF