Comparative evaluation of agroindustrial byproducts for the production of alkaline protease by wild and mutant strains of Bacillus subtilis in submerged and solid state fermentation

A systematic study on the characteristics and applications of laccases produced by fungi: insights on their potential for biotechnologies

Laccases are polyphenol oxidase enzymes and form the enzyme complex known for their role in wood decomposition and lignin degradation. The present study aimed to systematically review the state-of-the-art trends in scientific publications on laccase enzymes of the last 10 years. The main aspects checked included the laccase-producing fungal genera, the conditions of fungal growth and laccase production, the methods of immobilization, and potential applications of laccase. After applying the systematic search method 177 articles were selected to compound the final database. Although various fungi produce laccase, most studies were Trametes and Pleurotus genera. The submerged fermentation (SmF) has been the most used, however, the use of solid-state fermentation (SSF) appeared as a promising technique to produce laccase when using agro-industrial residues as substrates. Studies on laccase immobilization showed the covalent bonding and entrapment methods were the most used, showing greater efficiency of immobilization and a high number of enzyme reuses. The main use of the laccase was in bioremediation, especially in the discoloration of dyes from the textile industry and the degradation of pharmaceutical waste. Implications and consequences of all these findings in biotechnology and environment, as well as the trends and gaps of laccase research were discussed.

Influence of Bacillus Subtilis Fermentation on Content of Selected Macronutrients in Seeds and Beans

In this study, five plant matrices (pea, mung bean, lentils, soy and sunflower) were fermented using Bacillus subtilis var. natto. Then the process influence on the content of fatty acids and proteins was evaluated, depending on the fermentation length. Fermentation was conducted for 144 hours in controlled conditions of temperature and relative humidity (37°C, 75%). Samples for tests were collected every 24 hours. Gas chromatography coupled with triple quadrupole tandem mass spectrometry (GC-MS/MS) was used to evaluate fatty acids content in fermented seeds. Their composition was expressed as a percentage of the total quantity of fatty acids. The protein content in plant matrices was analysed with the modified Bradford protein assay, using the TECAN apparatus with the i-Control software, of the wave length of ʎ=595 nm. Studies showed that the prolonged fermentation time influenced an increase of polyunsaturated fatty acids (PUFA) content in all studied seeds. Promising results were obtained for soy, sunflower, and lentil seeds, amounting to 3.6%; 68.7% and 67.7%, respectively. This proves that the process of seed fermentation can be effectively used to increase their nutritional value.

Understanding the Basis of Occurrence, Biosynthesis, and Implications of Thermostable Alkaline Proteases

The group of hydrolytic enzymes synonymously known as proteases is predominantly most favored for the class of industrial enzymes. The present work focuses on the thermostable nature of these proteolytic enzymes that occur naturally among mesophilic and thermophilic microbes. The broad thermo-active feature (40-80 °C), ease of cultivation, maintenance, and bulk production are the key features associated with these enzymes. Detailing of contemporary production technologies, and controllable operational parameters including the purification strategies, are the key features that justify their industrial dominance as biocatalysts. In addition, the rigorous research inputs by protein engineering and enzyme immobilization studies add up to the thermo-catalytic features and application capabilities of these enzymes. The work summarizes key features of microbial proteases that make them numero-uno for laundry, biomaterials, waste management, food and feed, tannery, and medical as well as pharmaceutical industries. The quest for novel and/or designed and engineered thermostable protease from unexplored sources is highly stimulating and will address the ever-increasing industrial demands.

Microbial proteases: ubiquitous enzymes with innumerable uses

Proteases are ubiquitous enzymes, having significant physiological roles in both synthesis and degradation. The use of microbial proteases in food fermentation is an age-old process, which is today being successfully employed in other industries with the advent of ‘omics’ era and innovations in genetic and protein engineering approaches. Proteases have found application in industries besides food, like leather, textiles, detergent, waste management, agriculture, animal husbandry, cosmetics, and pharmaceutics. With the rising demands and applications, researchers are exploring various approaches to discover, redesign, or artificially synthesize enzymes with better applicability in the industrial processes. These enzymes offer a sustainable and environmentally safer option, besides possessing economic and commercial value. Various bacterial and fungal proteases are already holding a commercially pivotal role in the industry. The current review summarizes the characteristics and types of proteases, microbial source, their current and prospective applications in various industries, and future challenges. Promoting these biocatalysts will prove significant in betterment of the modern world.

The nucleotide composition of the spacer sequence influences the expression yield of heterologously expressed genes in Bacillus subtilis

Bacillus subtilis is a commonly used host for the heterologous expression of genes in academia and industry. Many factors are known to influence the expression yield in this organism e.g. the complementarity between the Shine-Dalgarno sequence (SD) and the 16S-rRNA or secondary structures in the translation initiation region of the transcript. In this study, we analysed the impact of the nucleotide composition between the SD sequence and the start codon (the spacer sequence) on the expression yield. We demonstrated that a polyadenylate-moiety spacer sequence moderately increases the expression level of laccase CotA from B. subtilis. By screening a library of artificially generated spacer variants, we identified clones with greatly increased expression levels of two model enzymes, the laccase CotA from B. subtilis (11 fold) and the metagenome derived protease H149 (30 fold). Furthermore, we demonstrated that the effect of the spacer sequence is specific to the gene of interest. These results prove the high impact of the spacer sequence on the expression yield in B. subtilis.