Valorization of durian peel as a carbon feedstock for a sustainable production of heterogeneous base catalyst,single cell oil and yeast-based biodiesel

The present study reports a successful attempt to produce single cell oil(SCO),heterogeneous base catalyst and yeast-based biodiesel from durian peel as a promising carbon feedstock by means of the waste-to-energy concept.For this purpose,first,durian peel(DP)was hydrolyzed by dilute sulfuric acid to obtain xylose-rich DP hydrolysate(XDPH)and post-hydrolysis DP solid residue(DPS).Candida viswanathii PSY8,a newly isolated oleaginous yeast,showed high SCO accumulation(5.1±0.1 g/L)and SCO content(35.3±0.13%)on undetoxified XDPH medium.A novel heterogeneous base catalyst(DPS-K)prepared from DPS by wet impregnation technique with KOH,exhibited considerable catalytic activity to convert SCO-rich wet yeast of C.viswanathii PSY8 into yeast-based biodiesel(FAME)via direct transesterification with a maximum FAME yield of 94.3%under optimal conditions(6 wt%catalyst,10:1 methanol to wet yeast ratio,75℃,and 2 h).Moreover,most of the yeast-based biodiesel properties obtained from the FAME profiles were correlated well with the biodiesel standards limit of Thai,ASTM D6751 and EN 14214.Additionally,the energy output of FAME produced about 37.5 MJ/kg was estimated.Thus,this present finding demonstrated the favorable strategy for sustainable and eco-friendly production of new generation biodiesel.

Saccharomyces cerevisiae in neuroscience:how unicellular organism helps to better understand prion protein?

The baker's yeast Saccharomyces(S.)cerevisiae is a single-celled eukaryotic model organism widely used in research on life sciences.Being a unicellular organism,S.cerevisiae has some evident limitations in application to neuroscience.However,yeast prions are extensively studied and they are known to share some hallmarks with mammalian prion protein or other amyloidogenic proteins found in the pathogenesis of Alzheimer's,Parkinson's,or Huntington's diseases.Therefore,the yeast S.cerevisiae has been widely used for basic research on aggregation properties of proteins in cellulo and on their propagation.Recently,a yeast-based study revealed that some regions of mammalian prion protein and amyloidβ1–42 are capable of induction and propagation of yeast prions.It is one of the examples showing that evolutionarily distant organisms share common mechanisms underlying the structural conversion of prion proteins making yeast cells a useful system for studying mammalian prion protein.S.cerevisiae has also been used to design novel screening systems for anti-prion compounds from chemical libraries.Yeastbased assays are cheap in maintenance and safe for the researcher,making them a very good choice to perform preliminary screening before further characterization in systems engaging mammalian cells infected with prions.In this review,not only classical red/white colony assay but also yeast-based screening assays developed during last year are discussed.Computational analysis and research carried out using yeast prions force us to expect that prions are widely present in nature.Indeed,the last few years brought us several examples indicating that the mammalian prion protein is no more peculiar protein–it seems that a better understanding of prion proteins nature-wide may aid us with the treatment of prion diseases and other amyloid-related medical conditions.