Production of polyhydroxyalkanoate [PHAs] and copolymer [P[HB-co-HV]] by soil bacterial isolates in batch and two-stage batch cultures

NINETY TWO local bacterial isolates, from the rhizosphere and soil around the root system of bean [Viciafaba] grown in Kalubia Governorate in Egypt, were bio-prospected for polyhydroxyalkanoate [PHA] accumulation. Three isolates accumulated >/=20% of PHAs, they were identified as Pseudomonas flu orescens S48, Bacillus megaterium 7A and B. megaterium UBFI9. The tested isolates gave the maximum PHAs content on basal medium containing glucose and ammonium sulfate at C/N ratio of 30/1 after 72 hr at 30°C using shake flask culture technique. Two-stage batch were implemented with varying loading levels of nitrogen and phosphorus, inoculated with washed cells. Nitrogen omission of 70% led to increase the PHAs content by 19%, 3% and 8.5% using washed cells of Ps. fluorescens S48, B. megaterium UBF 19 and Bacillus megaterium 7A, respectively comparing with batch production on the same medium after 72 hr. The Copolymer poly[hydroxybutyrate-co-hydroxyvalerate] [P [HB-co-HV]] content level was increased when valerie/glucose [V/G] was 0.19 mol.mo[-1] after 96 hr being 25.97% and 20.11% by Ps. fluorescens S48 and B. megaterium UBFI9, respectively and reached 23.73% by B. megaterium 7A at propionic/glucose [PIG] of 0.5 mol.mol[-1]. The corresponding highest values of valeric content of copolymer at V/G 3.08 mol.mol[-1] were 63%, 49% and 45%, respectively, comparing with other V/G ratios by using GC analysis . Replacing glucose with 2% corn oil or 1% soybean oil increased the PHAs content of Ps. fluorescens S48 cells to 54.21% and 52.12%, respectively, after 72

Biological evaluation of fungal deteriorated archeological wood [Islamic period] and the impact of using some fungicides

EIGHTY SEVEN fungal isolates were obtained from the surface of biodeteriorated ceiling wood [No.1803, 1539] from the Islamic museum, Cairo. Egypt [Islamic period]. Isolates belonging to eight main genera of fungi were identified, in the following frequencies: Acremonium 2,3%,, Alternaria 11,5%, Aspergillus 37.8%, Botryotrichum 2.3%,, Epicoccum 3.5%,, Fusarium 6.9%,, Penicillium 29,9°/o and Stemphvlium 5.7%. In a series of trials cellulase production was maximal for all fungal strains when grown on medium containing 4-6% of wood straw [at pH 4.5-5 after 1015 days at 30°C, whereas the maximum production of pectinase was attained on medium containing 6% wood straw at pH 4.5-5 after 10-15 days at 30°C -35°C. Application of the fungicides dichioroxylenol, paracresol anc pentachiorophenol are recommended for use at 1000, 500 and 1000 ppm respectively, based on protection of artificially infected wood. Infected wood lost 40.1% of its bending strength, loss was attained increased density and water absorption compared with non infected wood. The lowest bending strength loss was attained with dichloroxylenol [14.5%] followed by wood treatment with pentachiorophenol or paracresol [34.2%]