Microalgae are photosynthetic microorganisms that have a rapid growth cycle and carbon fixation ability. They have diverse cellular structures, ranging from prokaryotic cyanobacteria to more complex eukaryotic forms, which enable them to thrive in a variety of environments and support biomass production. They utilize both photosynthesis and heterotrophic pathways, indicating their ecological importance and potential for biotechnological applications. Reproducing primarily through asexual means, microalgae have complex cell cycles that are crucial for their growth and ability to adapt to changing conditions. Additionally, microalgae possess bioactive compounds that make them both nutritious and functional. Thanks to their content of proteins, lipids, carbohydrates, vitamins, and minerals, they play an important role in the development of functional food products, particularly by enhancing nutritional content and product quality. Furthermore, studies have demonstrated that algae and algal bioactive compounds support cardiovascular health, immune function, and gut health, especially in relation to obesity and other metabolic diseases. They also contribute to skin health and cognitive functions, including memory. This review article explores the biological, nutritional, and functional properties of microalgae based on the studies conducted.

Bioethanol production from renewable biomass sources has garnered significant interest due to its potential as a sustainable alternative to fossil fuels. In this study, we investigated the optimization of bioethanol production from molasses, a by-product of the sugar production process using Saccharomyces cerevisiae through Response Surface Methodology (RSM). Initially, the fermentation process was optimized using RSM, considering four independent variables: substrate concentration, pH, temperature, and fermentation time. Subsequently, the effects of these variables on bioethanol yield were evaluated, and a quadratic model was developed to predict the optimum conditions. Analysis of variance (ANOVA) indicated a high coefficient of determination (R²) for the model, suggesting its adequacy for prediction. The optimized conditions for bioethanol production were determined as follows: substrate concentration of 200 g L⁻¹, pH of 5.0, temperature of 30 °C and fermentation time of 72 h. Under these conditions, the predicted bioethanol yield was 84%. Overall, this study demonstrates the successful application of RSM for optimizing bioethanol production from molasses using S. cerevisiae, highlighting its potential as a promising feedstock for biofuel production.

In this study, hydrogen production through the hydrolysis, ethanolysis, and methanolysis reactions of NaBH₄ using adipic acid as a catalyst was investigated for the first time. Adipic acid solutions were prepared with methanol and ethanol at concentrations of 0.1, 0.2, 0.3, 0.4, and 0.5 M. In these reactions, NaBH₄-MR (methanolysis) and NaBH₄-ER (ethanolysis) reactions were carried out at 30, 40, and 50 °C with NaBH₄ concentrations of 1.25%, 2.5%, and 5%. Hydrolysis reactions (NaBH₄-HR) were conducted at 0.1 M under the same conditions. In the ethanolysis and methanolysis reactions at 30 °C, total hydrogen conversion was achieved at 0.3 M, 0.4 M, and 0.5 M. However, in the hydrolysis reactions, total hydrogen production was only obtained at 50 °C. It was observed that in the NaBH₄-MR and NaBH₄-ER reactions, total hydrogen conversion could be achieved within 4–5 s. The utilization of adipic acid as a catalyst for hydrogen production from NaBH₄ through ethanolysis and methanolysis reactions is proposed as a highly efficient and fast method, characterized by impressive conversion rates.

This study explores the use of sebacic acid, a catalyst not previously examined in the literature, for hydrogen production from NaBH₄ through methanolysis and ethanolysis reactions. Solutions of sebacic acid with concentrations ranging from 0.1 M to 0.4 M were prepared and tested. At a concentration of 0.3 M, 90% of the hydrogen from a 0.33 M NaBH₄ solution was released within 3 s, and full release was achieved in 4 s. Hydrogen production rates reached 4500 mL/min for ethanolysis and 4845 mL/min for methanolysis, with methanolysis reactions proving faster. The activation energies for methanolysis and ethanolysis were calculated as 7.17 kJ/mol and 52.3 kJ/mol, respectively. These results demonstrate that sebacic acid enables rapid and efficient hydrogen production, offering a new approach that significantly advances current hydrogen production methods.

Bu çalışmada, sentez gazından doğrudan dimetileter (DME) eldesi kapsamında ülkemizde bulunan klinoptilolit doğal zeolitinden yola çıkılarak D-Klinoptilolit (DK) isimli yeni katalizör sentezlenmiştir. Sentezlenen bu katalizör CuO/ZnO/Al2O3 (CZA) katalizörü ile 1/3 ve 2/1 oranında modifiye edilerek yeni katalizör bileşimleri elde edilmiştir. DME eldesi için sisteme besleme yapılacak olan gazların bileşimi % hacimce sırasıyla H2/CO/CO2/N2 = 36/18/10/36 olacak şekilde sisteme beslenmiştir. Gaz bileşimi oranları ile 2 farklı katalizör bileşimi, sabit yataklı, yüksek basınçlı ve sürekli akışlı reaksiyon sisteminde 250 °C, 275 °C ve 300 °C sıcaklıklarda, 30 ve 40 bar basınç altında ve 30,60,90 ve 120 dakikalarda aktivite testlerine tabi tutulmuştur. Katalizörlerin ve doğal zeolitin karakterizasyonu amacıyla X-işini difraktometresi (XRD), Yüzey Alanı Ölçüm Cihazı (BET), Termogravimetrik Analiz (TGA), Fourier Dönüşümlü Kizilötesi (FTIR) analizleri gerçekleştirilmiştir. Çalışmalarda 2 farklı oranda hazırlanan katalizör bileşimlerinin, farklı reaksiyon süreleri, reaksiyon basıncı ve reaksiyon sıcaklıklarında dimetileter seçiciliği (SDME) ve toplam karbon dönüşümüne (XC) etkileri incelenmiştir. DK+CZA (ağırlıkça 3/1) katalizör bileşimi 30 bar basınçta en yüksek % 69,5 olarak DME seçiciliğinde ürünler 250 °C’ de gerçekleşmiş olup, aynı sıcaklıkta zaman geçtikçe azalmıştır. Sıcaklık 275 ve 300 °C’ye çıktığında da başlangıçta DME seçiciliği tekrar artarken, aynı sıcaklıkta zaman ilerledikçe tekrar DME seçicilik oranında düşüş görünmüştür. DK+CZA (1/2) katalizör bileşimi 3 farklı sıcaklık ve sürelerde %10’un biraz üzerinde % DME seçiciliği sonuçlarını vermiştir. 40 bar basınçta ise DK+CZA (3/1) ve DK+CZA (1/2) oranındaki katalizör bileşimlerinin 250 °C ’de DME seçicikleri % 80’in üzerindedir. Çalışmalar sonucunda, katalizörlerin DME seçicilikleri karşılaştırıldığında DK+CZA (3/1) katalizör bileşiminin DME seçiciliğinin DK+CZA (1/2) katalizör bileşiminden daha fazla olduğu görülmüştür.