Utilization of microbial enzymes has been widely reported for centuries, but the commercial use of enzymes has been recently adopted. Particularly, cellulases have been utilized in various commercial sectors including agriculture, brewing, laundry, pulp and paper and textile industry. Cellulases of microbial origin have shown their potential application in various commercial sectors including textile, pulp and paper, laundry, brewing, agriculture and biofuel. Cellulases have diversified applications in the food industry, food service, food supply and its preservation. Indeed, cellulases can tenderize fruits, clarify the fruit juices, reduce roughage in dough, hydrolyze the roasted coffee, extract tea polyphenols and essential oils from olives and can increase aroma and taste in food items. However, their role in food industries has by and large remained neglected. The use of immobilized cellulases has further expanded their application in fruit and vegetable processing as it potentiates the catalytic power and reduces the cost of process. Technological and scientific developments will further expand their potential usage in the food industry.

Abiotic stresses are the most significant factors reducing agricultural productivity. Plants face extreme environmental conditions that may affect their biological mechanisms, thereby influencing their growth and development. Microorganisms possess substantial metabolites that aid in helping plants mitigate abiotic stresses. Plants’ interaction with microbes constitutes a diversified ecosystem, as sometimes both the partners share a mutualistic relationship. Endophytes, plant-growth-promoting rhizobacteria (PGPRs), and arbuscular mycorrhizal fungi (AMFs) are examples of microorganisms that play an essential role in alleviating abiotic stresses and, hence, improving plant growth. The plant–microbe interaction leads to the modulation of complex mechanisms in the plant cellular system. Moreover, the residing microbial flora also inhibits the phytopathogens, therefore, it becomes part of plants’ innate defense system. Keeping in view the growing environmental concerns, it is important to identify the role of the plant microbiome in the transportation of nutrients to maintain sustainable production. Furthermore, it is important to identify the factors enabling plants to recruit beneficial microbial species and how to deal with the potential pathogens. Therefore, this review aims to summarize the impacts of various abiotic stressors on agricultural productivity and the role of beneficial microorganisms in mitigating the negative effects of abiotic stresses. The literature review also shows that the beneficial microbes, including PGPRs, AMFs, and endophytes, adopt various mechanisms for ameliorating the negative effects of various stresses. It has been observed that biochar and microbes, either individually or in combination, can play a significant role in maintaining plant growth under stress conditions. Although conventional inoculation of beneficial microbes mitigates abiotic stresses and enhances productivity, the advancement in genetic engineering would help transfer specific genes from the microbes to plants to aid in abiotic stress mitigation.

The cell wall of brown algae contains alginate as a major constituent. This anionic polymer is a composite of β-d-mannuronate (M) and α-l-guluronate (G). Alginate can be degraded into oligosaccharides; both the polymer and its products exhibit antioxidative, antimicrobial, and immunomodulatory activities and, hence, find many commercial applications. Alginate is attacked by various enzymes, collectively termed alginate lyases, that degrade glycosidic bonds through β-elimination. Considering the abundance of brown algae in marine ecosystems, alginate is an important source of nutrients for marine organisms, and therefore, alginate lyases play a significant role in marine carbon recycling. Various marine microorganisms, particularly those that thrive in association with brown algae, have been reported as producers of alginate lyases. Conceivably, the marine-derived alginate lyases demonstrate salt tolerance, and many are activated in the presence of salts and, therefore, find applications in the food industry. Therefore, this review summarizes the structural and biochemical features of marine bacterial alginate lyases along with their applications. This comprehensive information can aid in the expansion of future prospects of alginate lyases.

Lignocellulose, the main component of plant cell walls, comprises polyaromatic lignin and fermentable materials, cellulose and hemicellulose. It is a plentiful and renewable feedstock for chemicals and energy. It can serve as a raw material for the production of various value-added products, including cellulase and xylanase. Cellulase is essentially required in lignocellulose-based biorefineries and is applied in many commercial processes. Likewise, xylanases are industrially important enzymes applied in papermaking and in the manufacture of prebiotics and pharmaceuticals. Owing to the widespread application of these enzymes, many prokaryotes and eukaryotes have been exploited to produce cellulase and xylanases in good yields, yet yeasts have rarely been explored for their plant-cell-wall-degrading activities. This review is focused on summarizing reports about cellulolytic and xylanolytic yeasts, their properties, and their biotechnological applications.