**2. Key challenges associated with biodegradation process**

Biodegradation may sometimes lead to incomplete mineralization of the total organic content, such as recalcitrant materials leaving unprocessed contaminants behind [4]. This could be due to the complex structure of the materials, higher molecular weight, crosslinking, shape, texture, surface area, and degradation rate [5]. For example, depending on the degree of crystallinity, orientation and packing of polymers, the degradation rate is severely affected. It has been observed that even under the same conditions, the degradation of amorphous regions of polycaprolactone (PCL) by filamentous fungi is much faster than the degradation of crystalline regions of PCL, where the amorphous regions may permit easy access to microbes during the degradation process [4]. Therefore, ensuring the complete or partial degradation of these complex substances to produce harmless products without secondary pollution is extremely important [5].

Additionally, the microbial biodegradation process also depends on various factors such as nutrient availability, microbe type, substrate properties, and environmental conditions such as pH, moisture content, and redox potential [6–8]. Generally, the redox potential relies on the presence of the electron acceptors at the active site, such as oxygen, nitrates, manganese oxides, iron oxides, sulfate, and triggering the aerobic or anaerobic biodegradation. Even though many of the microbes prefer physiological pH of 7.4 and a temperature of 37°C for their growth, certain microbes such as fungal species prefer an acidic environment. In contrast, some bacteria prefer relatively high temperatures for their optimal growth. Therefore, not exactly knowing the required growth conditions could be a significant factor contributing to the incomplete degradation of the substrate in some cases [7].

Furthermore, microbial metabolism in biodegradation is an energy transformation process that is solely governed by the functions of enzymes and the intermediates produced during the reactions [5]. Therefore, proper screening is required to identify the microbes with an inherent set of genes that are capable of degrading the contaminants, the factors and the conditions under which the population of these microbes could increase, and the synergic performance of these microbes with other technologies to establish an environmentally profitable biodegradation platform [9]. It has also been identified that more optimization procedures and scaling up are required for the biodegradation of large contaminated areas [10].

#### **3. Role of nanotechnology in biodegradation**

Biodegradable materials can be considered a preeminent group of materials that could also be called next-generation materials leading to zero global environmental pollution. Owing to this concern, the consumption of biodegradable materials, such as polymers, has increased two to three-fold in a broad spectrum of fields, including agriculture, automotive, packaging, energy and environment, and biomedical. But still, the contribution coming from the biodegradable polymers in said areas only accounts for 3–5% of total polymer consumption [11]. This lower contribution could be mainly due to the poorly addressed issues such as low durability, low performance, and high production cost [12].

In this context, combining the concept of biodegradation with nanotechnology could be identified as a more systemic and innovative approach to address the current issues with the biodegradation process [13]. Nanotechnology is an evolving branch of science that has diversified its application in many disciplines such as agriculture [14], healthcare [15], transportation [16], electronics [17],

#### *Novel Acumens into Biodegradation: Impact of Nanomaterials and Their Contribution DOI: http://dx.doi.org/10.5772/intechopen.98771*

food [18], water purification [19–25], and security [26]. Nanotechnology involves manipulating matter in 1–100 nm nanoscale to create materials where at least one of the dimensions of the particles in the nano range [27]. The combined approach of nanotechnology-mediated biodegradation could address a wide range of potential applications in agriculture, food packaging, environmental remediation, and healthcare while accounting for reduced costs and no impact on environmental pollution [12]. Nanomaterials have proven effective as excellent adsorbents, sensors, and catalysts for biodegradation purposes due to their specific surface area and high reactivity [28].

Furthermore, the presence of nanoparticles and microbes that are actively engaged in the biodegradation process has paved the way in improving growth profiles of microbes by acting as biodegradation enhancers [29–32]. It has also been observed that the integration of nanotechnology with the enzymatic pathways in the biodegradation process could lead to profound activity and improved reusability of the enzymes [13]. Nanoparticles have also performed as effective sensor systems to detect the utilization of the raw materials and the production of specific products, which provided an inference on the progression of the biodegradation process [33]. Hence, this process of nano-biodegradation would ultimately involve the reduction of accumulating harmful non-biodegradable materials in the environment [34, 35].

## **3.1 Factors affecting the performance of nanomaterials during biodegradation**
