In this study, effects of medium components and inoculum size on the protease production by Bacillus sp. EBTA6 that was isolated from a home-made Tarhana sample were investigated. The cell-free supernatant of bacterium cultured on a shaking incubator for 24 h was used to test protease activity as the response. With a total number of 11 factors, 12 different experiments were run and the highest experimental protease activity was measured as 2280.4 U/mL. Results were analyzed statistically by ANOVA and the most efficient factors were detected as yeast extract, dipotassium phosphate, casein, and peptone with a contribution of 93.78, 2.19, 1.96, 1.31%, respectively. For validation of the selected factors, a further experiment was performed by using of yeast extract (9.98 g/L), dipotassium phosphate (1.27 g/L), casein (8.69 g/L), and peptone (9.88 g/L) obtained from the design equation. The experimental response was found as 2411.4 U/mL which was only 5.5% higher than the predicted response showing that the model was applicable.

Nanoteknolojik yöntemlerle nano boyuta indirgenen metal partiküller temelde biyomedikal ve fizikokimya olmak üzere eczacılık, elektrik-elektronik, otomotiv sanayi, gıda sanayi gibi pek çok farklı alanda karşımıza çıkmaktadır. Fiziksel, kimyasal ve biyolojik olmak üzere üç farklı üretim yöntemi bulunan nanopartiküller ağırlıklı olarak kimyasal yöntemlerle üretilmektedir. Ancak fiziksel ve kimyasal yöntemler yüksek sıcaklık, yüksek basınç ve toksik kimyasalların kullanımını gerektirdiği için çevre dostu ve ekonomik değildir. Bu nedenle yeşil teknoloji olarak da adlandırılan, çevre dostu ve sürdürülebilir bir yaklaşım olan biyolojik yöntemlerle metal nanopartiküllerin üretimine olan ilgi son yıllarda artmıştır. Bazı bitki ekstraktlarıyla ve mikroorganizmaların hücre içi ve hücre dışı salgılarıyla birtakım indirgenme reaksiyonları gerçekleşmekte ve metal nanopartikülleri üretilmektedir. Bakteriler doğadaki çeşitlilikleri, kolay izole edilebilir olmaları ve nanopartikül üretimindeki kolaylıkları sebebiyle son yıllarda etkin birer nano fabrika görevi görmektedirler. Bu makalede, metal nanopartiküllerin bakteriyel yöntemlerle üretimleri ve uygulama alanları derlenmiştir.

Macrophomina phaseolina (Tassi) Goid. is a fungal pathogen causes charcoal rot disease (Sin: Rhizoctonia bataticola) and is responsible for significant yield losses in many plants. In our study, we aimed to evaluate the antagonistic ability of 39 different bacteria, isolated from the fields of sugar beet in 2019, against the pathogen Macrophomina phaseolina isolated from sugar beet, beans and chickpeas. Approximately 31% of the bacteria showed antibiosis effect against the pathogen. It was determined that the effectiveness level of Lelliottia amnigena, Bacillus atrophaeus, B.pumilus and B. cereus (7 isolates) was moderate to high against Macrophomina phaseolina. Bacillus atrophaeus (PTo15-1a) showed the highest efficacy of 80%, 72.94% and 82.35% against Macrophomina phaseolina of chickpea, bean and sugar beet respectively. Lelliottia amnigena (Pto 14-1b) was moderately effective (57.78%) against the chickpea isolate of the pathogen. It was observed that of the seven Bacillus cereus isolates used in the experiment, three isolates (Pto14-1a, Pto12-1b, Pto17-1b) were highly effective against the chickpea pathogen, two (Pto12-1b, Pto14-2b) against bean pathogen, and one (Pto15-1b) against sugar beet isolate. Results have shown varied level of antagonism by different test bacterial against different Macrophomina phaseolina isolates, while the highest level of antibiosis shown by Bacillus atrophaeus against all pathogenic isolates indicated that it can be a potential future bioagent in managing the disease.

Fire blight, affecting more than one hundred and thirty species in the Rosaceae, is probably the most destructive disease affecting pear and apple cultivars in many countries. Currently, there are no effective synthetic compounds with systemic properties. Other major problem is the occurrence and spread of strains of Erwinia amylovora with resistance to streptomycin and copper. Taken into consideration the human and environmental health, the use of biocontrol agents either as an alternative or as a supplement within an integrated fire blight management strategy has attracted worldwide attention. In this study, E. amylovora solution of 107 CFU ml-1 was treated with bio-control agents, Bacillus subtilis str. QST 713, B. amyloliquefaciens str. MBI 600 and their mixture (at solution densities of 106, 107 and 108 CFU ml-1 for each one) on Petri dishes, containing King’s B medium and, compared with positive (streptomycin sulphate) and negative (sterile distilled water) controls. In vivo studies were performed on two-year-old apple cv. Gala seedlings grown in 45-cm-diameter pots containing a sterilized mix of soil–sand–peat under controlled greenhouse conditions (85% relative humidity, 25°C temperature and 16h of day light). The plants were irrigated as needed by drip-irrigation and each pot received a mineral solution (NPK: 20–20–20) at 2 g l-1 twice. When plant shoots reached a length of 30-35 cm, bio-control agents, individually and their mixture, were applied to the plants by a hand-sprayer. Obtaining the data, 108 CFU ml-1 of Bacillus spp. suspension mixture showed strongest in vitro antibacterial effect (26mm) among the tested treatments after positive control streptomycin (28.6mm). Parallel to in vitro findings, the mixture was most effective against the pathogen on cv. Gala (66.03%). Findings show that the use of mixture of beneficial microorganisms with individual antagonistic properties against the pathogen can be an effective strategy as a natural alternative to agrochemicals in the scope of good agriculture practices.

To investigate some interesting functional properties of Bacillus spp. in cocoa fermentation processing, 702 strains of Bacillus sp. strains were isolated from six main Ivorian cocoa producer regions. Three mains technological and useful properties for good cocoa beans fermentation were monitored. Among the 386 pectinolytic Bacillus spp. strains, 86.79% of them were confirmed for enzymes production in liquid medium. These 335 pectinolytic Bacillus strains displayed variety of pectinolytic activity with 50.45% of them producing both pectinase and polygalacturonase (PG) enzymes. Among these 169 strains, 70% displayed both the ability to acidify the medium and to degrade the citrate. In mimic conditions of pH and temperature variations as for fermentation heap, 11 strains were able to maintain their activity ranged within 2.12 ± 0.02 to 0.41 ± 0.03 µmol/min/mg of proteins for PG and 2.36 ± 0.03 to 0.25 ± 0.03 µmol/min/mg of proteins for pectinase. Two species (T10T2 and T6HS10) identified as Bacillus subtilus and Bacillus thuringiensis, were selected as the best based on pectinase production level. They were able to continuously produce both pectinolytic enzymes in different conditions of organic acids and ethanol contents. The highlighted properties in this study and the performance of these two strains may make them best candidate as starters for cocoa fermentation control.