No abstract

Primary (or secondary) metabolites are produced by animals, plants, or microbial cell systems either intracellularly or extracellularly. Production capabilities of microbial cell systems for many types of primary metabolites have been exploited at a commercial scale. But the high production cost of metabolites is a big challenge for most of the bioprocess industries and commercial production needs to be achieved. This issue can be solved to some extent by screening and developing the engineered microbial systems via reconstruction of the genome‐scale metabolic model. The predicted genetic modification is applied for an increased flux in biosynthesis pathways toward the desired product. Wherein the resulting microbial strain is capable of converting a large amount of carbon substrate to the expected product with minimum by‐product formation in the optimal operating conditions. Metabolic engineering efforts have also resulted in significant improvement of metabolite yields, depending on the nature of the products, microbial cell factory modification, and the types of substrate used. The objective of this review is to comprehend the state of art for the production of various primary metabolites by microbial strains system, focusing on the selection of efficient strain and genetic or pathway modifications, applied during strain engineering.

No abstract

No abstract

Worldwide, a huge production of agro-industrial wastes is observed every year in the milling, brewing, agricultural, and food industries. Biochemical and bioactive substances can be produced from these agricultural wastes. Pineapple by-products, which consist of the peeled skin, core, crown end, etc., account for 60% of the weight of pineapple fruit and are disposed of as waste, causing disposal and pollution problems. The bioconversion process can utilize these wastes, which are rich in cellulose and hemicellulose, the main components, to produce value-added biochemicals/bioactive compounds such as pectin, citric acid, bromelain, ferulic acid, vanillin, and so on. Therefore, the sustainable solution for food and nutrition security can be supported by the utilization of pineapple waste. The proposed review article addresses approaches that do not generate waste while adding value. This can be achieved by using innovative biorefinery techniques such as green extraction and the use of green solvents. Microbial fermentation with an effective pretreatment (such as hydrothermal treatment and enzymatic treatment) to convert complex waste (pineapple fruit) into simple sugars and later fuel production are also discussed. The proposed review also provides a concise overview of the most recent research and developments in the field of advanced pineapple waste processing technologies.

The over dependency on conventional fossil energy resources is the consequence of high energy demand and excessive consumption of petroleum fuel, which turns out to be a major concern of 21st century. The burning of fossil fuel is an origin of greenhouse gas emission resulting in the utmost threat to environment subsequently which leads to global climate changes. As far as sustainability is concerned, fuels derived from organic or plant wastes overcome this downside and also are an established solution of the traditional oil resources depletion. In this context, exploration of agricultural residue appears to be a suitable alternate of non-renewable resources to support the environmental feasibility and meet the high energy crisis. Use of agricultural waste rather lignocellulosic biomass as a feedstock for biorefinery approach emerges to be an eco-friendly process for the production of biofuel and value-added chemicals intensifying the energy security. Therefore, a prospective choice of this renewable biomass for the synthesis of green fuel such as biobutanol, bioethanol keeps away food versus fuel dilemma and also comes up with favorable outcome in terms of cost effectiveness. Exploiting different agricultural biomass and exploring various biomass conversion techniques, biorefinery generates bioenergy in a strategic way which eventually fit in circular bioeconomy. The view of bioeconomy highlights the fruitful use of agricultural waste biomass in biorefinery acquiring such a system so that the by-products can be further utilized with low or no waste generation to maintain the sustainability and circularity of economy which are critically described.

Valorization of food and fruit wastes has the potential for the production of sustainable energy and biochemicals. Approximately 70% of the weight of the original jackfruit (Artocarpus heterophyllus L.) fruit is lost during processing as waste in the form of peeled skin and core, both of which have not been utilized and, thus contribute to disposal as well as pollution issues. The major components, cellulose, and hemicellulose, can be biologically transformed easily into bioenergy sources like ethanol, methanol, and butanol; valuable phenolics and biotechnological products like pectin, citric acid, bromelain, ferulic acid, and vanillin; and many other products. These residues can also be utilized as essential sources for the biological transformation process leading to the production of numerous products with added value, such as phenolic antioxidants, phenolic flavor compounds, and organic acids. Thus, the value addition of jackfruit waste can support the sustainable solution towards food and nutritional security. In this way, zero waste can be achieved through novel biorefineries which are critically highlighted in this paper. Furthermore, novel technologies for the conversion of jackfruit wastes are summarized with recent findings.

This research work has been carried out to establish the combinatorial impact of various fermentation medium constituents, used for poly‐β hydroxybutyrate (PHB) biosynthesis. Model development was performed with an optimized medium composition that enhanced the biosynthesis of PHB from the biowaste material Brewers’ spent grain (BSG). The latter was used as a carbon substrate in submerged fermentation with Bacillus sphaericus NCIM 2478. Three independent variables: BSG, yeast extract (YE), and salt solution concentration (SS) and one dependent variable (amount of PHB produced) were assigned. A total of 35 microbial fermentation trials were conducted by which a nonlinear mathematical relationship was established in terms of neural network model between independent and dependent variables. The resulting artificial neural networks (ANNs) model for this process was further optimized using a global genetic algorithm optimization technique, which predicted the maximum production of PHB (916.31 mg/L) at a concentration of BSG (50.12 g/L), concentration of YE (0.22 g/L), and concentration of SS (24.06%, v/v). The experimental value of the quantity of PHB (concentration ∼916 mg/L) was found to be very close to the value predicted by the ANN–GA model approach.