Optimization of Cellulase Production by Cohnella xylanilytica RU-14 Using Statistical Methods

In this study, the cellulase activity by bacterial strain Cohnella xylanilytica RU-14 was enhanced by optimizing the medium components using statistical methods of Plackett-Burman design (PBD) and response surface methodology-central composite design (RSM-CCD). The cellulase assay was performed using NS enzyme assay method for reducing sugars. By PBD, the most significant factors (CMC, pH, and yeast extract) in an enzyme production medium that influence cellulase production by RU-14 were identified. These identified significant variables were further optimized using RSM by CCD. It was found that under optimized conditions of the medium components, the cellulase activity increased three times up to 14.5 U/mL as compared to un-optimized conditions (5.2 U/mL) of the enzyme production medium. The optimized levels of the significant factors determined by the CCD were found to be CMC, 2.3% w/v, and yeast extract, 0.75% w/v, at pH 7.5. The most adequate temperature for cellulase production by the bacterial strain was found to be 37 °C using the one-factor-at-a-time method. Thus, statistical methods to optimize medium conditions to enhance cellulase production by Cohnella xylanilytica RU-14 were found successful.

Microorganisms in biological control strategies to manage microbial plant pathogens: a review

Chemical fertilizers and pesticides are an integral part of modern agriculture and are often associated with numerous environmental problems. Biological agents such as microorganisms can largely replace chemical fertilizers and pesticides. The proper use of selected microorganisms such as bacteria, fungi and viruses have several benefits for agriculture. These include a healthy soil microbiota, biological production of important compounds that promote plant health, and to be used as biocontrol agents (BCAs) that provide protection from plant pathogenic microorganisms. Scientists have found that several bacterial genera including Bacillus and Pseudomonas have antimicrobial activity against numerous pathogenic bacterial and fungal plant pathogens. Trichoderma, Aspergillus, and Penicillium are among the most common fungal genera used as BCAs against both bacterial and fungal plant pathogens. Several bacteriophages and mycoviruses are also found effective as BCAs against selective plant pathogens. Fusarium oxysporum is a commonly found microbial plant pathogen causing wilts and rots in plants. Overall, it can be concluded that the use of microbial BCAs is an effective practice against microbial plant pathogens.

Lectins: Biological significance to biotechnological application

Lectins are a set of non-enzymatic carbohydrate binding proteins appearing in all domains of life. They function to recognize, interact and bring about reversible binding of a specific sugar moiety present in a molecule. Since glycans are ubiquitous in nature and are an essential part of various biological process, the lectins are been investigated to understand the profile of these versatile but complex glycan molecule. The knowledge gained can be used to explore and streamline the various mechanisms involving glycans and their conjugates. Thus, lectins have gained importance in carbohydrate-protein interactions contributing to the development in the field of glycobiology. This has led to a deeper understanding of the importance of saccharide recognition in life. Since their discovery, the lectins have become a great choice of research in the field of glycobiology and their biological significances have recently received considerable attention in the biocontrol field as well as medical sectors.

20-O-acylcamptothecin derivatives: evidence for lactone stabilization

Convincing UV and NMR spectrophotometric evidence is presented which demonstrates that at physiological pH, 7.4, 20-O-acyl derivatives of camptothecin (CPT) are substantially more stable in the lactone form than the 20-OH parent. Additionally, it was determined by HPLC analysis that the lactone ring of a 20-O-ether derivative of CPT underwent endocyclic ring opening at pH > or =8.5, while the lactone ring of 20-O-acyl CPT derivatives remained unaffected. PEG (and other smaller alkyl) 20-O-acyl-CPT derivatives released native CPT at pH > 9.5, which arises from exocyclic cleavage, thus precluding isolation of any open CPT acyl PEG (or alkyl) carboxylate forms.