Biological methods for detoxification of corn stover and corn starch pyrolysis liquors

Biological methods were developed to detoxify corn stover and corn starch pyrolysis liquors produced at 400--500°C. Prokaryotic and eukaryotic suspended cells and biofilms were employed for the detoxification process. The continuous of detoxification process was monitored by measuring the change in dissolved oxygen and pH. Total phenolic assay, change in UV absorbance spectra, GC-MS analysis and bioassay were performed to determine the detoxification. Pseudomonas putida and Streptomyces setonii biofilms, developed on Plastic Composite Supports (PCS) fixed to agitator shaft of benchtop computer controlled bioreactor, detoxified 10 and 25% (v/v) diluted corn stover and corn starch pyrolysis liquor (Des and Dst), while mixed culture biofilms detoxified 50% (v/v) Dcs and Dst.;Ligninolytic enzymes of Phanerochaete chrysosporium were also employed to detoxify the Dcs and Dst in shake flask cultures. The detoxification was determined by measuring the activity of lignin peroxidase (LiP), mangenase peroxidase (MnP), total phenolic compounds reduction, GC-MS analysis, and bioassay. Ph. chrysosporium culture detoxified 10 and 25% (v/v) Dcs and Dst, but not 50% (v/v) Des and Dst. The involvement of ligninolytic enzymes in the detoxification process were confirmed by adding ligninolytic enzymes inhibitors, sodium azide and cycloheximide to culture medium and by employing concentrated crude enzyme to detoxify 10% (v/v) Dcs.;In a subsequent study, the ligninolytic enzymes were produced by Ph. chrysosporium PCS biofilm in stirred tank bioreactor. Fourteen repeated batch fermentations were performed with different culture conditions. The differences in enzymes production between the batches were determined statistically by comparing the activity of LiP and MnP. All batch conditions evaluated enhanced the production of at least one of the enzymes. In batch C3V0 11 and C3V3 8 (continuous aeration, 300 agitation, and addition of veratryl alcohol on day zero or three) LiP and MnP were produced on day three and reached a peak on day six. However, in batch C3VM0 14 (continuous aeration, 300 agitation, and addition of veratryl alcohol and MnSO4 on day zero) LiP and MnP were produced earlier, on day three, and decreased by day six

الفطريات المحلله للسليولوز في المملكة العربية السعودية

Thirty fungal species belonging to fifteen genera were collected from 30 soil samples on cellulose Czapek agar. The highest number of fungal species was isolated from Dammam (20 species) followed by Niomas (18 species), Makkah and Riyadh (17 species each), Tabouk (16) species and Jizan (11 species). The most frequent genera isolated were Aspergillus, Pencillium, Alternaria, Ulocladium and Curvularia. Throughout this study, six fungal species belonging to four genera; Ulocladiun septosporum, Emericella nidulans, Trichoderma harzianum, T. koningii, T. pseudokoningii and Cochliobolus lunatus were found to be new records in Saudi Arabian soils.تم في هذه الدراسة جمع عينات تربة من ست مدن في المملكة العربية السعودية هي الدمام ، النماص ، مكة المكرمة ، الرياض ، تبوك وجيزان ، حيث تم عزل وتعريف ثلاثون نوعاً من الفطريات ينتمون إلى خمسة عشر جنساً ذات قدرة على تحليل السليلوز وأظهرت عينات الدمام أعلى معدل من الأنواع الفطرية (20 نوع ) تتبعها النماص (18 نوع )، مكة والرياض (17 نوع )، تبوك (19 نوع ) وجيزان (11 نوع ) . وتلين أن الأجناس السائدة المعزولة هي Aspergillus, Penicillium, Alternaria, Ulocladium and Curvularia كما تم خلال هذه الدراسة عزل وتعريف سته أنواع فطرية ينتمون إلى أربعة أجناس لم يسجل وجودها من قبل في المملكة وهي. Trichoderma pseudokoningii, T. harzianum, T. koningii, Ulocadium septosporum, Emericella nidulans and Cochliobolus lunatus

Efficacy of neutral and negatively charged liposome-loaded gentamicin on planktonic bacteria and biofilm communities

We investigated the efficacy of liposomal gentamicin formulations of different surface charges against Pseudomonas aeruginosa and Klebsiella oxytoca. The liposomal gentamicin formulations were prepared by the dehydration-rehydration method, and their sizes and zeta potential were measured. Gentamicin encapsulation efficiency inside the liposomal formulations was determined by microbiologic assay, and stability of the formulations in biologic fluid was evaluated for a period of 48h. The minimum inhibitory concentration and the minimum bactericidal concentration were determined, and the in vitro time kill studies of the free form of gentamicin and liposomal gentamicin formulations were performed. The activities of liposomal gentamicin in preventing and reducing biofilm-forming P. aeruginosa and K. oxytoca were compared to those of free antibiotic. The sizes of the liposomal formulations ranged from 625 to 806.6 nm in diameter, with the zeta potential ranging from -0.22 to -31.7 mV. Gentamicin encapsulation efficiency inside the liposomal formulation ranged from 1.8% to 43.6%. The liposomes retained .60% of their gentamicin content during the 48 h time period. The minimum inhibitory concentration of neutral formulation was lower than that of free gentamicin (0.25 versus 1 mg/L for P. aeruginosa and 0.5 versus 1 mg/L for K. oxytoca). The negatively charged formulation exhibited the same bacteriostatic concentration as that of free gentamicin. The minimum bactericidal concentration of neutral liposomes on planktonic bacterial culture was twofold lower than that of free gentamicin, whereas the negatively charged formulations were comparable to free gentamicin. The killing time curve values for the neutral negatively charged formulation against planktonic P. aeruginosa and K. oxytoca were better than those of free gentamicin. Furthermore, liposomal formulations prevent the biofilm-formation ability of these strains better than free gentamicin. In summary, liposomal formulations could be an effective lipid nanoparticle to combat acute infections where planktonic bacteria are predominant

Nucleotide substitution rates of diatom plastid encoded protein genes are correlated with genome architecture

Diatoms are the largest group of heterokont algae with more than 100,000 species. They are photosynthetic, unicellular eukaryotes that contribute ~ 45% of global primary production and inhabit marine, aquatic and terrestrial ecosystems. Despite their ubiquity and environmental significance very few diatom plastid genomes (plastomes) have been sequenced and studied. This study explored the pattern of diatom plastid nucleotide substitution rates across the entire suite of plastome protein-coding genes for 40 taxa representing the major clades. Substitution rate acceleration was lineage specific with the highest rates in the araphid 2 taxon Astrosyne radiata and radial 2 taxon Proboscia sp. Rate heterogeneity was also evident in different functional classes of genes. Similar to land plants, proteins genes involved in photosynthetic metabolism have substantially lower rates than those involved in transcription and translation. Significant positive correlations were identified between rates and measures of genomic rearrangement, but not plastome size. This work advances the current understanding of diatom plastomes and provides a foundation for future studies of their evolution.</jats:p

Supplementary Information for the evolution of the plastid genomes in diatoms

This file contains supplementary information for the book chapter. Table A to G contains additional information of the genome size, genome rearrangement, and correlation between genome rearrangement etc