Polyhydroxybutyrate (PHB) is a biosynthetic and biodegradable plastic which attracts attention du to its properties. Out of nine Actinomycetes isolates obtained from different soil samples, the PHB accumulating isolate was identified by molecular studies and was identified as Streptomyces incanus BK128. Different agricultural waste (wheat bran, rice bran, rice straw and molasses) were employed for polyhydroxybutyrate (PHB) production as the main carbon source. Some supplements such as (0.4 g) ammonium sulphate were used to optimize the PHB production medium. The maximum PHB production was achieved with wheat bran (1.9g/l). Different parameters including; the initial pH of the medium, ammonium chloride concentration and inoculum size; were carried out under shaking flask conditions (150 rpm) at 30ºC for 5 days of incubation to enhance the PHB production. The maximum PHB production (2.82gl-1) was achieved at pH 6.5, (2%) NH 4 CL and 5 ml inoculum size, respectively. The effect of gamma irradiation on the activity of Streptomyces incanus BK 128 towards PHB production showed that, at dose level 1.5 kGy, the maximum PHB production obtained was 3.39 gl-1 .

Citric acid is in greater demand globally as a result of both population growth and industrialization. Aspergillus niger is a workhorse for the production of citric acid. Cane molasses have been chosen as a novel and economically viable substrate as a result of the rising demand for citric acid and the need for substitute materials as substrates in recent years. Therefore, the present study was conducted to improve citric acid production from A. niger using by-product of sugar (sugarcane molasses) through gamma radiation. Aspergillus niger was isolated from soil and confirmed by molecular identification based on beta tubulin gene sequencing which compared with available beta tubulin gene sequencing in the NCBI database. The NCBI database showed the highest percentage of similarity being 100 with A. niger. The fermentation process was performed in shaking flasks using sugarcane molasses. Data revealed that significantly highest production of citric acid (31.30 ±0.17 g/L) was obtained in a medium containing (15%) substrate level. In addition, the maximum productivity of citric acid was achieved at pH 6. Spore suspensions of A. niger were subjected to different doses of gamma radiation. Results clarified that the maximum amount (42.82 ±0.62 g/L) of citric acid was observed at 1.0 KGy. The amount of acid produced was increased by 1.11 fold higher than the control by the addition of 3% (v/v) ethanol after 24 hour of fermentation time. Moreover, the addition of 0.15% K4Fe (CN)6 enhanced the citric acid manufacturing. Furthermore, citric acid productivity from immobilized gamma irradiated A. niger spores was increased by 1.2 times more than that of the free ones. Citric acid was separated from the fermentation broth by precipitation method using CaCl2. In addition, FT-IR Analysis of the extracted citric acid from A. niger confirmed that there is no change in the main characteristic absorption bands of the standard citric acid.

T HE AMOUNT of chemosynthetic plastic waste increases every year and the exact time for its degradation is unknown. Polyhydroxybutyrates (PHBs) are macromolecules synthesized by bacteria. Because of their fast degradability under natural environmental conditions, PHBs were selected as alternatives for the production of biodegradable plastics. In the present study, soil samples were collected from the rhizosphere region of seven different crops commonly grown in Egyptian soils and used to collect Streptomyces isolates from Benha, Al-Qalioubia Governorate. A total of 50 representative actinomycete isolates (6 from lettuce, 5 from garlic, 9 from onion, 6 from zucchini, 9 from eggplant, 8 from wheat, 7 from alfalfa rhizosphere soil) were collected and refined. Screening was performed by staining colonies of isolates with Sudan Black B. The dye Sudan Black was used as a screening tool for PHB production. Streptomyces isolates were identified by morphological, biochemical and molecular methods. A phylogenetic tree constructed based on the resulting 16S rRNA-encoding gene sequences was examined. A Streptomyces isolate turned out to be Streptomyces incanus BK128. PHBpurified extract of Streptomyces incanus BK128 was characterized using FTIR in comparison to standard PHB. The authors investigated the effect of gamma irradiation on the activity of Streptomyces incanus BK128 on PHB production.

Plants have been used since ancient times in folk medicine, involving all medical traditions. Many plants and plant derived antimicrobial components are used in folklore therapeutics for oral hygiene. Salvia officinalis and Aloe vera extracts were assayed for the evaluation of their antimicrobial activity against two pathogenic bacteria that were identified biochemically and by VITEK2 system. The test of antibiotic susceptibility showed the resistance of the two isolates to at least ten antibiotics used in this study. In vitro investigations of nine Egyptian plant extracts showed that ethanolic Aloe vera and ethanolic Salvia officinalis extracts could exhibit an antibacterial activity against human pathogenic isolates and inhibition zones of 16.333±0.58 and 13.0 ±1.0 mm were observed when Salvia officinalis extract applied against the above-mentioned bacteria, while the inhibition zones of 13.333±0.58 and 11.667±0.58 mm were observed by Aloe vera extract.