The novel extreme obligate alkaliphilic Bacillus marmarensis DSM 21297 is known to produce polyhydroxybutyrate (PHB). However, the detailed mechanism of PHB synthesis in B. marmarensis is still unknown. Here, we investigated which metabolic pathways and metabolic enzymes are responsible for PHB synthesis in order to understand the regulatory pathway and optimize PHB synthesis in B. marmarensis. In accordance with the fact that beta-galactosidase, 3-hydroxyacyl-CoA dehydrogenase, and Enoyl-CoA hydratase together with acyl-CoA dehydrogenase and lipase were annotated in B. marmarensis according to the RAST server, we used glucose, lactose, and olive oil to understand the preferred metabolic pathway for the PHB synthesis. It was found that B. marmarensis produces PHB from glucose, lactose, and olive oil. However, the highest PHB titer and the highest amount of PHB synthesized per dry cell mass (YP/X) were achieved in the presence of lactose, as compared to glucose and olive oil. Additionally, in the absence of peptone, the amount of PHB synthesized is reduced for each carbon source. Interestingly, none of the carbon sources studied yielded an efficient PHB synthesis, and supplementation of the medium with potassium ions did not enhance PHB synthesis. According to these experimental results and the presence of annotated metabolic enzymes based on the RAST server, PHB accumulation in the cells of B. marmarensis could be improved by the level of the expression of 3-hydroxybutyryl-CoA dehydrogenase (1.1.1.157), which increases the production of NADPH. Additionally, the accumulation of 3-hydroxyacyl-CoA could enhance the production of PHB in B. marmarensis in the presence of fatty acids. To our knowledge, this is the first report investigating the regulatory system involved in the control of PHB metabolism of B. marmarensis.

Bu çalışma, Adana'nın Seyhan ilçesindeki apartmanlardaki su depolarının fizikokimyasal ve mikrobiyolojik kalitesinin belirlenmesi amacıyla yapılmıştır. Bu amaç doğrultusunda 53 apartmandan depo giriş, depo çıkış ve 1. kat olmak üzere toplamda 159 adet su numunesi toplandı. Su numunelerinde fizikokimyasal özelliklerden tat, koku, bulanıklılık, toplam sertlik, pH ve bakiye klor ölçümü yapılırken, mikrobiyolojik olarak 37 °C'de koloni sayımı, Enterekok, E. coli, total koliform bakterilerin varlığı araştırıldı. Depo girişinden, yani şebekeden alınmış olan su örneklerinde %0,63 oranında total koloni sayımında, %1,89 oranında ise total koliform bakteri, %0 E. coli uygunsuzluğuna rastlanmıştır. Çıkış sularında ise %0,63 enterekok, %14,5 total koloni sayımı, %5 total koliform ve %0 E. coli bakteri tespit edilmiştir. Saha da yapılan ölçümlerde bakiye klor sadece 4 apartmanın su deposunda ölçülebilmiştir. Su numunelerinin geneli orta sertlikte olduğu gözlemlenmiştir. Alınan su numunelerinde 2 istisnai örnek dışında renk, tat, bulanıklılık ve koku problemi de bulunmamaktadır. Örneklerin pH düzeyleri incelendiğinde şebeke suyunun 6,9-8,4 değerleri arasında ve ortalama 7,4 değerinde olduğu ölçülmüştür. Yapılan çalışma sonunda, suyun bina içi su yapılarına kadar temiz bir şekilde ulaştığı varsayılsa bile suların depolandığı su depolarının çok kritik bir öneme sahip olduğu görülmüştür.

No abstract

Caves are extreme ecosystems that are too limited in nutrient with stable temperature, high humidity. Gilindire Cave, located in Mersin; Turkey, contains samples from Ice Age and is the only place known to represent evidence of the last climate changes in in the Eastern Mediterranean. Therefore, Gilindire Cave distinguishes itself from other caves in Turkey with its "representative" and "individual" features. In this study bacterial load of Gilindire Cave was investigated by using culture dependent and culture independent methods. Samples were cultured on R2A petri plates and distinct looking colonies were isolated. After isolation, 16S rRNA PCR analysis was performed. 58 isolates were obtained after cultivation experiments. However, further investigation was completed on 30 individual isolate due to elimination of isolates. Crystal formation was investigated with B-4 media and it was seen that 3 of the isolates was unable grow on this media while the rest 27 were able to grow successfully. Twenty of the isolates were chosen and send to analysis. Most abundant phyla included Actinobacteria (39%) followed by Proteobacteria (%33), Firmicutes (17%) and Bacteriodetes (5,5%) as well as uncultured organism (5,5%) was found, usable results could not be obtained from two of the isolates.