Bacillus species continue to be dominant bacterial workhorses in microbial fermentations. Bacillus subtilis (natto) is the key microbial participant in the ongoing production of the soya-based traditional natto fermentation, and some Bacillus species are on the Food and Drug Administration's GRAS (generally regarded as safe) list. The capacity of selected Bacillus strains to produce and secrete large quantities (20-25 g/L) of extracellular enzymes has placed them among the most important industrial enzyme producers. The ability of different species to ferment in the acid, neutral, and alkaline pH ranges, combined with the presence of thermophiles in the genus, has lead to the development of a variety of new commercial enzyme products with the desired temperature, pH activity, and stability properties to address a variety of specific applications. Classical mutation and (or) selection techniques, together with advanced cloning and protein engineering strategies, have been exploited to develop these products. Efforts to produce and secrete high yields of foreign recombinant proteins in Bacillus hosts initially appeared to be hampered by the degradation of the products by the host proteases. Recent studies have revealed that the slow folding of heterologous proteins at the membrane-cell wall interface of Gram-positive bacteria renders them vulnerable to attack by wall-associated proteases. In addition, the presence of thiol-disulphide oxidoreductases in B. subtilis may be beneficial in the secretion of disulphide-bond-containing proteins. Such developments from our understanding of the complex protein translocation machinery of Gram-positive bacteria should allow the resolution of current secretion challenges and make Bacillus species preeminent hosts for heterologous protein production. Bacillus strains have also been developed and engineered as industrial producers of nucleotides, the vitamin riboflavin, the flavor agent ribose, and the supplement poly-gamma-glutamic acid. With the recent characterization of the genome of B. subtilis 168 and of some related strains, Bacillus species are poised to become the preferred hosts for the production of many new and improved products as we move through the genomic and proteomic era.

Microbial cellulases have shown their potential application in various industries including pulp and paper, textile, laundry, biofuel production, food and feed industry, brewing, and agriculture. Due to the complexity of enzyme system and immense industrial potential, cellulases have been a potential candidate for research by both the academic and industrial research groups. Nowadays, significant attentions have been devoted to the current knowledge of cellulase production and the challenges in cellulase research especially in the direction of improving the process economics of various industries. Scientific and technological developments and the future prospects for application of cellulases in different industries are discussed in this paper.

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A contemporary approach to bacterially mediated zinc (Zn) biofortification offers a new dimension in the crop improvement program with better Zn uptake in plants to curb Zn malnutrition. The implication of Zn solubilizing bacteria (ZSB) represents an inexpensive and optional strategy for Zn biofortification, with an ultimate green solution to enlivening sustainable agriculture. ZSB dwelling in the rhizospheric hub or internal plant tissues shows their competence to solubilize Zn via a variety of strategies. The admirable method is the deposition of organic acids (OAs), which acidify the surrounding soil environment. The secretion of siderophores as a metal chelating molecule, chelating ligands, and the manifestation of an oxidative–reductive system on the bacterial cell membrane are further tactics of bacterially mediated Zn solubilization. The inoculation of plants with ZSB is probably a more effective tactic for enhanced Zn translocation in various comestible plant parts. ZSB with plant growth-enhancing properties can be used as bioelicitors for sustainable plant growth via the different approaches that are crucial for plant health and its productivity. This article provides an overview of the functional properties of ZSB-mediated Zn localization in the edible portions of food crops and provides an impetus to explore such plant probiotics as natural biofortification agents.