In silico proteomic analysis provides insights into phylogenomics and plant biomass deconstruction potentials of the Tremelalles

Basidiomycetes populate a wide range of ecological niches but unlike ascomycetes, their capabilities to decay plant polymers and their potential for biotechnological approaches receive less attention. Particularly, identification and isolation of CAZymes is of biotechnological relevance and has the potential to improve the cache of currently available commercial enzyme cocktails toward enhanced plant biomass utilization. The order Tremellales comprises phylogenetically diverse fungi living as human pathogens, mycoparasites, saprophytes or associated with insects. Here, we have employed comparative genomics approaches to highlight the phylogenomic relationships among thirty-five Tremellales and to identify putative enzymes of biotechnological interest encoded on their genomes. Evaluation of the predicted proteomes of the thirty-five Tremellales revealed 6,918 putative carbohydrate-active enzymes (CAZYmes) and 7,066 peptidases. Two soil isolates, Saitozyma podzolica DSM 27192 and Cryptococcus sp. JCM 24511, show higher numbers harboring an average of 317 compared to a range of 267–121 CAZYmes for the rest of the strains. Similarly, the proteomes of the two soil isolates along with two plant associated strains contain higher number of peptidases sharing an average of 234 peptidases compared to a range of 226–167 for the rest of the strains. Despite these huge differences and the apparent enrichment of these enzymes among the soil isolates, the data revealed a diversity of the various enzyme families that does not reflect specific habitat type. Growth experiment on various carbohydrates to validate the predictions provides support for this view. Overall, the data indicates that the Tremellales could serve as a rich source of both CAZYmes and peptidases with wide range of potential biotechnological relevance

Draft Genome Sequence of the Oleaginous Yeast Saitozyma podzolica (syn. Cryptococcus podzolicus) DSM 27192

We report here the draft genome of Saitozyma podzolica DSM 27192 sequenced based on PacBio chemistry. This yeast isolate produces large amounts of single-cell oil (SCO) and gluconic acid (GA). Information from the genome sequence will provide additional insight into the genetic mechanism of SCO and GA metabolism in this organism

Direct transesterification of microalgae after Pulsed Electric Field ( PEF ) treatment

Background Lipid extraction is a major bottleneck for the commercialization of microalgae due to energy costs involved during solvent recycling. Direct transesterification offers the possibility to bypass the extraction step by immediately converting the lipids to fatty acids methyl esters (FAMEs). In this study, the efficiency of direct transesterification after pulsed electric field (PEF) was evaluated. Freshly harvested Auxenochlorella protothecoides (A. protothecoides), cultivated either autotrophically or mixotrophically, was subjected to PEF. Two treatment energies were tested, 0.25 MJ/kgdw and 1.5 MJ/kgdw and results were compared with conventional two-step transesterification. Results For autotrophically grown A. protothecoides, the percentage of the total FAMEs recovered from untreated biomass and microalgae treated with 0.25 MJ/kgdw was 30% for both cases while for 1.5 MJ/kgdw it was 65%. A 24-h incubation step between PEF-treatment and direct transesterification significantly improved the results. Untreated biomass remained stable with 30% of FAMEs, while with both treatment energies a 97% FAME recovery was achieved. However, for mixotrophic A. protothecoides the process was not as effective. Approximately 30% of FAMEs were recovered for all three conditions immediately after PEF with only a marginal increase after incubation. The reason for this different behavior of the two cultivation modes is unknown and under investigation. Conclusions Overall, the synergy between PEF and direct transesterification was proven to have potential, in particular for autotrophic microalgae. Its implementation and further optimization in a biorefinery therefore merits further attention

Direct transesterification of microalgae after Pulsed Electric Field ( PEF ) treatment

Background Lipid extraction is a major bottleneck for the commercialization of microalgae due to energy costs involved during solvent recycling. Direct transesterification offers the possibility to bypass the extraction step by immediately converting the lipids to fatty acids methyl esters (FAMEs). In this study, the efficiency of direct transesterification after pulsed electric field (PEF) was evaluated. Freshly harvested Auxenochlorella protothecoides (A. protothecoides), cultivated either autotrophically or mixotrophically, was subjected to PEF. Two treatment energies were tested, 0.25 MJ/kgdw and 1.5 MJ/kgdw and results were compared with conventional two-step transesterification. Results For autotrophically grown A. protothecoides, the percentage of the total FAMEs recovered from untreated biomass and microalgae treated with 0.25 MJ/kgdw was 30% for both cases while for 1.5 MJ/kgdw it was 65%. A 24-h incubation step between PEF-treatment and direct transesterification significantly improved the results. Untreated biomass remained stable with 30% of FAMEs, while with both treatment energies a 97% FAME recovery was achieved. However, for mixotrophic A. protothecoides the process was not as effective. Approximately 30% of FAMEs were recovered for all three conditions immediately after PEF with only a marginal increase after incubation. The reason for this different behavior of the two cultivation modes is unknown and under investigation. Conclusions Overall, the synergy between PEF and direct transesterification was proven to have potential, in particular for autotrophic microalgae. Its implementation and further optimization in a biorefinery therefore merits further attention

A Study of Carbon Formation and Prevention in Hydrocarbon-Fueled SOFC

The formation and removal of the carbonaceous deposits formed by n-butane and liquid hydrocarbons, such as n-decane and proprietary light and heavy naphthas, between 973 and 1073 K on YSZ and ceria-YSZ, has been studied to determine conditions for stable operation of direct-utilization SOFC. First, it is shown that deactivation of SOFC with Cu-ceria-YSZ anodes operating on undiluted n-decane, a mixture of 80% n-decane and 20% toluene, or light naphtha at temperatures above 973 K is due to filling of the pores with polyaromatic compounds formed by gas-phase, free-radical reactions. Formation of these compounds occurs at a negligible rate below 973 K but increases rapidly above this temperature. The rate of formation also depends on the residence time of the fuel in the anode compartment. Because steam does not participate in the gas-phase reactions, carbonaceous deposits could form even at a H2O:C ratio of 1.5, a value greater than the stability threshold predicted by thermodynamic calculations. Temperature-programmed-oxidation (TPO) measurements with 20% H2O in He demonstrated that carbon deposits formed in pure YSZ were unreactive below 1073 K, while deposits formed on ceria-YSZ could be removed at temperatures as low as 923 K. Based on these results, we discuss strategies for avoiding carbon formation during the operation of direct-utilization anodes on oil-based liquid fuels

Co-production of single cell oil and gluconic acid using oleaginous Cryptococcus podzolicus DSM 27192

Background: The co-production of single cell oil (SCO) with value-added products could improve the economic viability of industrial SCO production. The newly isolated oleaginous yeast Cryptococcus podzolicus DSM 27192 was able to co-produce SCO intracellularly and gluconic acid (GA) extracellularly. In this study, the metabolic regulation of carbon distribution between SCO and GA through process optimization was comprehensively investigated. Results: The carbon flow distribution between SCO and GA was significantly influenced by the cultivation conditions, such as nitrogen sources, glucose concentration and dissolved oxygen concentration. It was found that organic nitrogen sources were beneficial for SCO accumulation, while GA production was decreased. Dissolved oxygen concentration (DOC) was found to enhance SCO accumulation, while high glucose concentration was more favorable for GA accumulation. Hence, a two-stage DOC or glucose concentration-controlled strategy was designed to improve cell growth and direct carbon distribution between SCO and GA. Moreover, C. podzolicus DSM 27192 could degrade its stored lipids to synthesize GA in the late stationary phase, although considerable amounts of glucose remained unconsumed in the culture medium, indicating the importance of fermentation time control in co-production systems. All these observations provide opportunity to favor either the production of SCO or GA or rather their simultaneous production. Conclusions: Co-production of SCO and GA by C. podzolicus DSM 27192 can improve the economical value for microbial lipid-derived biodiesel production. Moreover, the results of the proposed co-production strategy might give guidance for other co-production systems

Real-Time Nanoparticle–Cell Interactions in Physiological Media by Atomic Force Microscopy

Particle–cell interactions in physiological media are important in determining the fate and transport of nanoparticles and biological responses to them. In this work, these interactions are assessed in real time using a novel atomic force microscopy (AFM) based platform. Industry-relevant CeO2 and Fe2O3 engineered nanoparticles (ENPs) of two primary particle sizes were synthesized by the flame spray pyrolysis (FSP) based Harvard Versatile Engineering Nanomaterials Generation System (Harvard VENGES) and used in this study. The ENPs were attached on AFM tips, and the atomic force between the tip and lung epithelia cells (A549), adhered on a substrate, was measured in biological media, with and without the presence of serum proteins. Two metrics were used to assess the nanoparticle cell: the detachment force required to separate the ENP from the cell and the number of bonds formed between the cell and the ENPs. The results indicate that these atomic level ENP–cell interaction forces strongly depend on the physiological media. The presence of serum proteins reduced both the detachment force and the number of bonds by approximately 50% indicating the important role of the protein corona on the particle cell interactions. Additionally, it was shown that particle to cell interactions were size and material dependent