ABSTRACT
We undertook numerical and experimental studies to develop a better incineration method for the destruction of CCl4. A phenomenological model for the turbulent reaction of CCl4, including a flame inhibition feature, has been successfully incorporated into a commercial code, simulating the incineration processes of this compound. The gaseous flow solution was obtained using SIMPLEST, a derivative of Patankar's SIMPLE algorithm, with a k-epsilon turbulence model. A modified fast chemistry turbulent reaction model was developed to describe the flame inhibition due to the presence of CCl4, considering the corresponding burning velocity data of these mixtures. An experiment was carried out on a small-scale, transportable, dump-type incinerator, which warrants a sufficient residence time and effective turbulent mixing by the formation of a strong recirculation region in a combustor. To this end, the specific configuration of the incinerator was manufactured to consist of two opposing jets and a rearward facing step. The calculated data were in close agreement with the experimental data for the concentrations of major species, such as CCl4, and HCl, together with the temperature profiles. The dump incinerator satisfied the orders required by the EPA of 99.99% ("4 nines") DRE for hazardous waste incinerators.
Subject(s)
Carbon Tetrachloride/chemistry , Models, Theoretical , Refuse Disposal , Air Movements , Gases , IncinerationABSTRACT
Five putative phosphoinositide-specific phospholipases C (PLC) genes were identified in three species of filamentous fungi. Using polymerase chain reaction with degenerate oligonucleotide primers, gene fragments encoding amino acid sequences homologous to PLCs of mammals and other organisms were amplified: one sequence from Botryotinia fuckeliana, one from Aspergillus nidulans, and three from Neurospora crassa. The molecular cloning and sequencing of a putative PLC gene (BCPLC1) from B. fuckeliana showed that it encoded a polypeptide containing X and Y domains, the two conserved regions found in all known PLCs. The hypothetical gene product of BCPLC1 was of delta type in its primary structural organization. The identification of three PLC genes in N. crassa shows that multiple PLC isozymes also occur in microbial eukaryotes.
Subject(s)
Ascomycota/enzymology , Ascomycota/genetics , Genes, Fungal , Type C Phospholipases/genetics , Amino Acid Sequence , Animals , Aspergillus nidulans/enzymology , Aspergillus nidulans/genetics , Base Sequence , Cloning, Molecular , DNA Primers/genetics , DNA, Fungal/genetics , Molecular Sequence Data , Neurospora crassa/enzymology , Neurospora crassa/genetics , Phosphatidylinositol Diacylglycerol-Lyase , Restriction Mapping , Sequence Homology, Amino AcidABSTRACT
As an initial step to develop a DNA-mediated transformation system using benomyl resistance as a dominant selectable marker in the phytopathogenic fungus Botryotinia fuckeliana (anamorph, Botrytis cinerea), we have constructed a phage lambda genomic DNA library of a benomyl-resistant strain 91T-1, and a beta-tubulin-encoding gene benA was isolated, cloned and sequenced. Southern blot analysis suggested that a single copy of benA is present in the genome of B. fuckeliana. The benA gene is composed of seven exons which are separated by six introns of 52 to 135 bp. The intron consensus sequences are similar to those of other fungal genes. The deduced amino acid sequence (447 amino acid residues) is highly homologous to those of other fungal beta-tubulin-encoding genes. Comparison of the sequences around codons 198 and 200 in benomyl-resistant and sensitive strains revealed that the benAHR allele from the benomyl-resistant strain 91T-1 contained a mutation at codon 198 from GAG (Glu) to GCG (Ala), which has been correlated with high resistance to benzimidazole fungicides including benomyl in various filamentous fungi.
