Enhanced production of amylase, pyruvate and phenolic compounds from glucose by light-driven Aspergillus niger–CuS nanobiohybrids

Abstract

BACKGROUND: The demand for value-added compounds such as amylase, pyruvate and phenolic compounds produced by biological methods has prompted the rapid development of advanced technologies for their enhanced production. Nanobiohybrids (NBs) make use of both the microbial properties of whole-cell microorganisms and the light-harvesting efficiency of semiconductors. Photosynthetic NBs were constructed that link the biosynthetic pathways of Aspergillus niger with CuS nanoparticles. RESULTS: In this work, NB formation was confirmed by negative values of the interaction energy, i.e., 2.31 × 108 to −5.52 × 108 kJ mol−1 for CuS–Che NBs, whereas for CuS–Bio NBs the values were −2.31 × 108 to −4.62 × 108 kJ mol−1 for CuS–Bio NBs with spherical nanoparticle interaction. For CuS–Bio NBs with nanorod interaction, it ranged from −2.3 × 107 to −3.47 × 107 kJ mol−1. Further, the morphological changes observed by scanning electron microscopy showed the presence of the elements Cu and S in the energy-dispersive X-ray spectra and the presence of CuS bonds in Fourier transform infrared spectroscopy indicate NB formation. In addition, the quenching effect in photoluminescence studies confirmed NB formation. Production yields of amylase, phenolic compounds and pyruvate amounted to 11.2 μmol L−1, 52.5 μmol L−1 and 28 nmol μL−1, respectively, in A. niger–CuS Bio NBs on the third day of incubation in the bioreactor. Moreover, A niger cells–CuS Bio NBs had amino acids and lipid yields of 6.2 mg mL−1 and 26.5 mg L−1, respectively. Furthermore, probable mechanisms for the enhanced production of amylase, pyruvate and phenolic compounds are proposed. CONCLUSION: Aspergillus niger–CuS NBs were used for the production of the amylase enzyme and value-added compounds such as pyruvate and phenolic compounds. Aspergillus niger–CuS Bio NBs showed a greater efficiency compared to A. niger–CuS Che NBs as the biologically produced CuS nanoparticles had a higher compatibility with A. niger cells. © 2022 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).