Industrial biology plays a crucial role in the fields of medicine, health, food, energy, and so on. However, the lack of efficient genetic engineering tools has restricted the rapid development of industrial biology. Recently, the emergence of clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) system brought a breakthrough in genome editing technologies due to its high orthogonality, versatility, and efficiency. In this review, we summarized the barriers of CRISPR/Cas9 and corresponding solutions for efficient genetic engineering in industrial microorganisms. In addition, the advances of industrial biology employing the CRISPR/Cas9 system were compared in terms of its application in bacteria, yeast, and filamentous fungi. Furthermore, the cooperation between CRISPR/Cas9 and synthetic biology was discussed to help build complex and programmable gene circuits, which can be used in industrial biotechnology.

Solving the plastic crisis requires high recycling quotas and technologies that allow open loop recycling. Here a biological plastic valorization approach consisting of tandem enzymatic hydrolysis and monomer conversion of post-consumer polyethylene terephthalate into value-added products is presented. Hydrolysates obtained from enzymatic degradation of pre-treated post-consumer polyethylene terephthalate bottles in a stirred-tank reactor served as the carbon source for a batch fermentation with an engineered Pseudomonas putida strain to produce 90mg/L of the biopolymer cyanophycin. Through fed-batch operation, the fermentation could be intensified to 1.4 g/L cyanophycin. Additionally, the upcycling of polyethylene terephthalate monomers to the biosurfactants (hydroxyalkanoyloxy)alkanoates and rhamnolipids is presented. These biodegradable products hold significant potential for applications in areas such as detergents, building blocks for novel polymers, and tissue engineering. In summary, the presented bio-valorization process underscores that addressing challenges like the plastic crisis requires an interdisciplinary approach.