Eficiência de produtos biológicos na coinoculação de sementes de soja

O objetivo deste trabalho foi verificar o potencial uso de produtos biológicos comerciais na coinoculação com Bradyrhizobium japonicum no tratamento de semente da soja. O experimento foi realizado em papel germitest e o cultivo em vasos. Foram realizados sete tratamentos com cinco repetições, sendo: T1 – testemunha, T2 –Bradyrhizobium japonicum, T3 – B. japonicum + Azospirillum brasilense, T4 – B. japonicum + Bacillus subtilis, T5 – B. japonicum + Bacillus amyloliquefaciens, T6 – B. japonicum + Bacillus methylotrophicus e T7 – B. japonicum + Bacillus pumilus. As variáveis analisadas foram germinação (G), germinação de plântulas normais (GN), índice de velocidade de emergência (IVE), crescimento parte aérea em vaso (CAV) e papel germitest (CAG), de raíz em vaso (CRV) e papel germitest (CRG). Os dados foram submetidos a análise dos pressupostos e determinados a partir do teste de Tukey a 5% de probabilidade e realização da análise de componentes principais (ACP). A coinoculação de B. japonicum + A. brasilense promoveu ganhos de enraizamento e germinação em plântulas de soja. A coinoculação com B. pumilus apresentou potencial de efeito semelhante a associação de B. japonicum + A. brasilense. A associação com B. methylotrophicus apresentou melhor enraizamento em vaso (CRV) que os demais tratamentos. O uso de BPCP’s em associação com B. japonicum potencializa o desenvolvimento inicial da plântula.

Bioprospecção e caracterização de bactérias produtoras de celulase a partir do solo do Cerrado brasileiro

Este trabalho descreve a bioprospecção e a caracterização de bactérias produtoras de celulase isoladas de solo obtido em uma região preservada do bioma Cerrado, em Uberaba, Brasil. A atividade celulolítica foi confirmada em 14 das 84 linhagens bacterianas isoladas. De acordo com a quantificação enzimática, cinco isolados foram selecionados como os melhores produtores de celulase e com base no sequenciamento parcial do gene 16S rRNA foram identificadas como Bacillus siamensis (isolado AB-9; 5.000U/mL), Bacillus toyonensis (isolado AB-1; 4.630U/mL), Bacillus methylotrophicus (isolados MB-3; 4.236U/mL e MP-7; 4.282U/mL) e Bacillus drentensis (isolado ME-2; 4.444U/mL). O extrato enzimático obtido de B. siamensis AB-9 foi o mais estável em diferentes valores de pH (2-8), mantendo sua atividade celulolítica, enquanto B. toyonensis AB-1 e B. methylotrophicus MP-7 produziram celulases com atividade máxima em pH 7 e 8. As celulases produzidas por B. siamensis AB-9 e B. toyonensis AB-1 apresentaram alta atividade enzimática em todas as temperaturas analisadas (10-80°C), enquanto as celulases de B. methylotrophicus MB-3 apresentaram atividade máxima na faixa de 20-70°C. Até o momento, esta é a primeira vez que bactérias produtoras de celulase isoladas do bioma Cerrado brasileiro na região do Triângulo Mineiro com potencial aplicação biotecnológica são descritas.

Effect of applying Bacillus-based products on the production of strawberry cultivars

Oneof the factors that can compromise the strawberry culture is theuse of seedlings without phytosanitary quality. The aim of this study was to evaluate the use of three biological products in the production of strawberry cultivars. For this, six cultivars ('Camino Real', 'Festival', 'Oso Grande', 'Albion', 'San Andreas'and 'Camarosa') were selected to receive the following treatments: T1) Onix (2.4 mL) + Qualit (0.6 mL) (Bacillus methylotrophicus+ Trichoderma asperellum); T2) Rhizos (2.4 mL) + Qualit (0.6 mL) (Bacillus subtilis+ Trichoderma asperellum) and T3) Control. After the production cycle, the total production (g kg-1), estimated average production (kg ha-1) and number of fruits in each plot were evaluated. 'Festival' and 'Oso Grande' were the most productive cultivars and their greatest yields were observed in the presence of Bacilluscompared to control. Plants grown in the presence of B. methylotrophicusand B. subtilisshowed a higher number of fruits. The use of these biological products is important for strawberry cultivation.

Estimation of the biological efficiency of prospective dominant strains of bacteria in the rhizosphere of spring barley

An important task of modern agricultural production is the creation of new environmentally friendly agricultural technologies aimed at increasing the productivity of crops. Spring barley is an important forage crop, which occupies a significant place in the balance of concentrated feed. Therefore, our study is quite relevant today, given the trend towards the transition to organic farming and the development of biological fertilizers. The aim of the study was to determine the efficiency of inoculation with dominant strains of rhizosphere bacteria Phyllobacterium ifriqiyense 1 and Bacillus methylotrophicus 10 seeds of spring barley and physiological parameters of growth and development of the culture in model conditions. The task of the study is to determine the titer of viable bacteria, exposure of spring barley seeds in bacterial suspension, accounting for the growth of spring barley plants and fixing its biometric parameters after bacterization; determination of physiological parameters of plant growth and development in model conditions. Research methods – microbiological (direct calculation of viable colony-forming units using Goryaev's camera). Indicators of photosynthetic activity of the leaf were determined using the biophysical method of induction of chlorophyll fluorescence by a portable device "Floratest". The results of studies – the strain Phyllobacterium ifriqiyense 1 showed the maximum biological effect on the growth of test culture of barley (including dilution of culture fluid). It was found that treatment with bacterial suspensions of Phyllobacterium ifriqiyense 1 and Bacillus methylotrophicus 10 promotes the activation of the functions of the photosynthetic apparatus of barley plants in the laboratory. Prospects – rhizosphere microorganisms are important components of the environment in the early stages of ontogeny of cereals, so the use of dominant inoculating bacteria has scientific and practical significance in the optimization of agricultural production technologies.

Pengaruh Aplikasi Plant Growth Promoting Rhizobacteria terhadap Pertumbuhan dan Hasil Tanaman Bawang Merah (Allium cepa L. Aggregatum group)

Salah satu upaya penanganan penyakit moler bawang merah dilakukan melalui aplikasi Trichoderma. Aplikasi Trichoderma pada bawang merah memiliki beberapa keunggulan, yaitu mampu mensintesis hormon pertumbuhan tanaman. Terdapat jenis mikroba lain yang juga mampu meningkatkan fitohormon pada tanaman, yaitu Plant Growth Promoting Rhizobacteria (PGPR). Tujuan dari penelitian ini adalah untuk mengetahui dan menentukan isolat PGPR yang memiliki pengaruh paling baik terhadap pertumbuhan dan hasil bawang merah varietas Crok Kuning di lahan sawah. Penelitian ini menggunakan Rancangan Acak Kelompok Lengkap (RAKL) faktor tunggal dengan tiga blok sebagai ulangan. Faktor perlakuan yang digunakan adalah lima isolat PGPR, yaitu: Bp.25.7 Bacillus subtilis, BrSG.5 Bacillus amyloliquofaciens, Bp.25.2 Bacillus methylotrophicus, BrsM.4 Burkholderia cepacia, danBp.25.6 Bacillus amyloliquofaciens dengan dua kontrol, yaitu kontrol positif berupa Trichoderma dan kontrol negatif tanpa aplikasi perlakuan. Hasil penelitian menunjukkan bahwa pemberian perlakuan isolat Bp.25.2 Bacillus methylotrophicus pada bawang merah menyebabkan Laju Asimilasi Bersih (LAB) bawang merah lebih tinggi dibandingkan dengan pemberian perlakuan empat isolat PGPR lainnya maupun kontrol, tetapi sama baiknya dengan pemberian perlakuan Trichoderma. LAB yang tinggi menyebabkan Laju Pertumbuhan Tanaman (LPT) bawang merah dengan pemberian perlakuan Bp.25.2 Bacillus methylotrophicus yang lebih tinggi dibandingkan dengan BrSG.5 Bacillus amyloliquofaciens dan Bp.25.6 Bacillus amyloliquofaciens, tetapi sama baiknya dengan pemberian perlakuan dua isolat PGPR lainnya, kontrol, maupun Trichoderma. Pemberian aplikasi lima isolat PGPR sama baiknya dengan aplikasi Trichoderma dalam meningkatkan pertumbuhan tanaman bawang merah pada variabel luas permukaan daun dan bobot kering total dibandingkan kontrol. Peningkatan variabel pertumbuhan ini tidak diikuti oleh peningkatan variabel hasil dan produktivitas bawang merah tidak berbeda nyata antar perlakuan.

Antifungal Activity of Volatile Organic Compounds Produced by Bacillus methylotrophicus and Bacillus thuringiensis against Five Common Spoilage Fungi on Loquats

Loquat fruit is one of the most perishable fruits in China, and has a very limited shelf life because of mechanical injury and microbial decay. Due to an increasing concern about human health and environmental security, antagonistic microorganisms have been a potential alternative for fungicides to control postharvest diseases. In this work, the antifungal effect of volatile organic compounds (VOCs) produced by Bacillus methylotrophicus BCN2 and Bacillus thuringiensis BCN10 against five postharvest pathogens isolated from loquat fruit, Fusarium oxysporum, Botryosphaeria sp., Trichoderma atroviride, Colletotrichum gloeosporioides, and Penicillium expansum were evaluated by in vitro and in vivo experiments. As a result, the VOCs released by BCN2 and BCN10 were able to suppress the mycelial growth of all targeted pathogens according to inhibition ratio in the double petri-dish assay as well as disease incidence and disease diameter on loquat fruits. The main volatile compounds were identified by solid-phase microextraction (SPME)-gas chromatography. These VOCs produced by the two strains played complementary roles in controlling these five molds and enabled loquat fruits to keep fresh for ten days, significantly. This research will provide a theoretic foundation and technical support for exploring the functional components of VOCs applicable in loquat fruit preservation.

Three-phase partitioning and immobilization of Bacillus methylotrophicus Y37 cellulase on organo-bentonite and its kinetic and thermodynamic properties

In this study, for the first time Bacillus methylotrophicus Y37 cellulase was purified and recovered in a single step by three-phase partitioning (TPP). The optimal purification parameters for TPP were 40% ammonium sulfate saturation (m/v) with a 1.0:1.0 (v/v) ratio of crude extract:t-butanol, which gave 5.8-fold purification with 155% recovery of cellulase. Non-covalent immobilization of the partitioned cellulase was performed using bentonite as a support material. The activity observed in the 20th experiment was 100%. The optimal pH values and temperatures determined for the free enzyme and the immobilized enzyme were 5.0 and 6.0 and 45°C and 50°C, respectively. The Arrhenius activation energy (Ea) of the immobilized enzyme was lower than that of the free enzyme, whereas the Michaelis–Menten constant (Km) and maximum velocity (Vm) of the immobilized enzyme increased. The turnover number (kcat) and the catalytic performance (kcat/Km) demonstrated the improved catalytic properties of the immobilized enzyme compared to the free enzyme. Immobilization of cellulase is thermodynamically preferred.