Assessment of Biochemical Changes of Four Aspergillus Species Grown on the Medium from Agricultural Wastes

Abstract

Hazardous disposal of agricultural wastes (AW) has adverse environmental consequences, including water and air pollution and the potential for disease outbreaks. On the other hand, the utilization of AW represents a missed opportunity to harness a valuable economic resource. This study was conducted with the objective of utilizing a composite medium comprising agricultural waste to cultivate Aspergillus species and assessing its impact on the species' internal chemical composition compared to malt extract media (ME). Our findings demonstrate that the agricultural waste-based medium is abundant in essential nutrients, including soluble proteins and sugars, and is also enriched with a variety of secondary metabolites. Consequently, this Change in the growth medium induces changes in the physical characteristics of fungal biomass, such as color and texture, along with a high content of biomass proteins and secondary metabolites, including phenols, flavonoids, carotenoids, and antioxidants. The A. avenaceous gave the highest biomass (1.1412 ± 0.4 g), while the A. niger gave the highest value of proteins (16.06 ± 0.4 mg/g), phenols (33.37 ± 0.8 mg/g), flavonoids (4.84 ± 0.4 mg/g), carotenoids (1.131 ± 0.09 mg/g). A. carbonarius gave the highest value of antioxidants (IC50 = 0.28 ± 0.06 mg/mL). In contrast, using malt extract as a growth medium results in high carbohydrate and lipid production; A. flavus showed the highest value for fats (56.6 ± 0.9 mg/g), whereas A. carbonarius showed the highest value for sugars (167.1 ± 6.2 mg/g). Additionally, the malt extract medium contributed to low levels of secondary metabolites, which was offset by an increase in the protein bands of the fungal species. This research recommends the use of agricultural wastes to grow fungi species as an environmentally and economically important microbiological application.