Limited information is available that seed biopriming with plant growth-promoting Enterobacter spp. play a prominent role to enhance vegetative growth of plants. Contrary to Enterobacter cloacae, Enterobacter hormaechei is a less-studied counterpart despite its vast potential in plant growth-promotion mainly through the inorganic phosphorus (P) and potassium (K) solubilization abilities. To this end, 18 locally isolated bacterial pure cultures were screened and three strains showed high P-and K-solubilizing capabilities. Light microscopy, biochemical tests and 16S rRNA gene sequencing revealed that strains 15a1 and 40a were closely related to Enterobacter hormaechei while strain 38 was closely related to Enterobacter cloacae (Accession number: MN294583; MN294585; MN294584). All Enterobacter spp. shared common plant growth-promoting traits, namely nitrogen (N 2) fixation, indole-3-acetic acid production and siderophore production. The strains 38 and 40a were able to produce gibberellic acid, while only strain 38 was able to secrete exopolysaccharide on agar. Under in vitro germination assay of okra (Abelmoschus esculentus) seeds, Enterobacter spp. significantly improved overall germination parameters and vigor index (19.6%) of seedlings. The efficacy of root colonization of Enterobacter spp. on the pre-treated seedling root tips was confirmed using Scanning Electron Microscopy (SEM). The pot experiment of bioprimed seeds of okra seedling showed significant improvement of the plant growth (> 28%) which corresponded to the increase of P and K uptakes (> 89%) as compared to the uninoculated control plants. The leaf surface area and the SPAD chlorophyll index of bioprimed plants were increased by up to 29% and 9% respectively. This report revealed that the under-explored species of P-and K-solubilizing Enterobacter hormaechei sp. with multiple plant beneficial traits presents a great potential sustainable approach for enhancement of soil fertility and P and K uptakes of plants.

Aptamers are a group of synthetic single-stranded nucleic acids. They are generated from a random library of single-stranded DNA or RNA by a technology named systematic evolution of ligands by exponential enrichment (SELEX). SELEX is a repetitive process to select and identify suitable aptamers that show high affinity and specificity towards target cells. Great strides have been achieved in the design, construction, and use of aptamers up to this point. However, only a small number of aptamer-based applications have achieved widespread commercial and clinical acceptance. Additionally, finding more effective ways to acquire aptamers with high affinity remains a challenge. Therefore, it is crucial to thoroughly examine the existing dearth and advancement in aptamer-related technologies. This review focuses on aptamers that are generated by SELEX to detect pathogenic microorganisms and mammalian cells, as well as in cell-internalizing SELEX for diagnostic and therapeutic purposes. The development of novel aptamer-based biosensors using optical and electrical methods for microbial detection is reported. The applications and limitations of aptamers are also discussed.

The extraction of soluble hydrolysate protein and sugar from a biomass cocktail of defatted soybean meal (DSM) and jackfruit peel (JP) was examined using microwave-alkaline hydrolysis by varying the NaOH concentrations (0.04–0.11 M) and residence times (2–11 min). Based on the central composite design, the optimized parameters were achieved at 0.084 M NaOH concentration (100 mL), for 8.7 min at 300 W microwave power level to obtain the highest protein (5.31 mg/mL) and sugar concentrations (8.07 mg/mL) with > 75% recovery. Both raw and detoxified hydrolysate (using activated carbon) were correspondingly biocompatible with Enterobacter hormaechei strain 40a (P > 0.05) resulting in maximal cell counts of > 10 log CFU/mL. The optimized hydrolysate was prepared as an additive in molasses-alginate bead encapsulation of strain 40a. Further evaluation on phosphate and potassium solubilization performance of the encapsulated strain 40a exhibited comparable results with those of free cell counterpart (P > 0.05). The DSM-JP hydrolysate cocktail holds potential as a carrier additive of encapsulated-cell bead biofertilizers in order to sustain bacterial cell quality and consequently improve crop growth and productivity.

3 hormaechei sp. improves the early vegetative growth and 4 the P and K uptake of okra (Abelmoschus esculentus) 5 seedling 6 Muhamad Aidilfitri Abstract 23 Limited information is available that seed biopriming by plant growth-promoting bacteria such 24 as those among Enterobacter spp. play a prominent role to enhance vegetative growth of plants.25 Contrary to Enterobacter cloacae, Enterobacter hormaechei is a less-studied counterpart 26 despite its vast potential in plant growth-promotion mainly through the inorganic phosphorus 27 (P) and potassium (K) solubilization abilities. To this end, 18 locally isolated bacterial pure 28 cultures screened and three strains showed high P-and K-solubilizing capabilities. Light 29 microscopy, biochemical tests and 16S rRNA gene sequencing revealed that strains 15a1 and 30 40a were closely related to Enterobacter hormaechei while strain 38 was closely related to 31 Enterobacter cloacae (Accession number: MN294583; MN294585; MN294584). All 32 Enterobacter spp. shared common plant growth-promoting traits, namely N 2 fixators, indole-33 3-acetic acid producers and siderophore producers. Gibberellic acid was only produced by 34 strain 38 and 40a, while exopolysaccharide formation was solely detected on agar containing 35 colonies of strain 38. Under in vitro germination assay of okra (Abelmoschus esculentus) seeds, 36 Enterobacter spp. significantly improved overall germination parameters and vigor index 37 (19.6%) of seedlings. The efficacy of root colonization of Enterobacter spp. on the pre-treated 38 seedling root tips was confirmed using Scanning Electron Microscopy (SEM). The pot 39 experiment of bioprimed seeds of okra seedling showed significant improvement of the plant 40 growth (> 28%) which corresponded to the increase of P and K uptakes (> 89%) as compared 41 to the uninoculated control plants. The leaf surface area and the SPAD chlorophyll index of 42 bioprimed plants were increased up to 29% and 9% respectively. This report revealed that the 43 under-explored species of P-and K-solubilizing Enterobacter hormaechei sp. with multiple 44 plant beneficial traits hold as a good potential sustainable approach for enhancement of soil 45 fertility and P and K uptakes of plants. 3 46

The understanding of microorganism's biodiversity in the peatland soil through non-cultivation based approach provide important inputs towards prediction of the ecosystem response towards the changing environment. The challenge that hindered the success to obtain high quality DNA from peat soil lies in the physicochemical characteristics such as low pH and high humic acid content. There are two general approaches that have been extensively applied for soil microbial DNA extraction, which are direct DNA extraction protocol and indirect DNA extraction protocol. The only step differentiate between these two protocols is the later includes additional cell separation method from soil micro-aggregates preceding DNA extraction process. Therefore, several improved and modified methods in conventional DNA extraction and purification methods are reviewed in this paper to cater all the highlighted issues as to obtain high-quality DNA for peatland metagenomics soil studies. INTRODUCTIONSoil is a huge reservoir of carbon sources and organic matter, providing valuable nutrient-rich habitat for growth and energy for diverse organism. The biological interaction amongst soil indigenous microorganisms is significant to maintain soil function, composition and fertility. In estimation, up to 10 8 microbial cells were found in a gram of bulk soil with at most 100 species diversity [1]. The role and complexity of soil microbial metabolisms and interactions have been broadly exploited with respect to various biotechnological applications such as plant microbial inoculation, bioremediation, enzyme isolation and bioactive compounds production [2-9].The microbial abundance has been extensively explored by the classical laboratory cultivation techniques which however bears only limited biodiversity of approximately less than 1% cultivable microbes from the natural environments [10][11][12]. These conventional culture-dependent methods heavily rely on the optimum supply of nutrient sources, growth media and other physical and chemical parameters such as pH, temperature and metal ions concentration that suit optimally to only certain groups of microorganisms hence dramatically underestimating the accurate number of microorganisms in the nature. The limitation of these growth techniques hinders the process of comprehensive soil microbial community analysis making it almost impossible and practically tedious to uncover more uncultivable and novel microorganism species.To overcome such limitations, the later development of rapid and direct access of genetic material from environmental samples without cultivation has been introduced. The term metagenomics is then used to describe the study of the collective unknown genetic material which give insights not just into the taxonomy diversity of the environmental samples but also their ecological function [13]. This discovery has revolutionized the way we perceive and understand the microbial world due to their ability to expose the previously unknown microscopic life diversity. However, the...