Influence and strategies for enhanced biohydrogen production from food waste

The growing of food waste generation is gradually becoming a global problem due to the improper management of it. According to the Food and Agriculture Organization (FAO), United Nation, more than 1.3 million tonnes of food is being wasted. Food waste and food processing waste are abundant - which are rich in organic acids and nutrients. These acids and nutrients can be utilized for attractive and efficient generation of renewable and sustainable fuels such as biohydrogen through fermentation process. Many investigations have revealed a significant biohydrogen generation using food wastes from restaurant, dining hall and food processing industries. During the hydrogen generation through fermentation, several parameters influence the yield of hydrogen. Some of them are method of pre-treatment, feed composition, fermentation temperature, culture and substrate, solution pH, etc. Also, the presence of inert intermediates produced during the reaction in fermentation process reduces the process efficiency. Few studies have shown that the use of nanoparticles in fermentation process along with the application of short & cyclic ultrasound is beneficial to increase the process efficiency. The augmentation in ultrasound-assisted process is due to the physical and chemical effects of ultrasound in the medium through the phenomenon of cavitation. During the transient collapse of cavitation bubbles, several reactive species are produced which further participate in the thermochemical and biochemical reactions. Thus, enhances the rate of reaction by annihilation the complex sugars in food wastes. Additionally, the cavitational effect helps to reduce the growth of hydrogen inhibiting microorganism in the feed. This review demonstrates the potentiality of food waste for production of biohydrogen through fermentation process including a brief overview of process parameters that affect the fermentation process. Additionally, an overview of integrated fermentative process coupled with nanoparticles and ultrasound is also discussed for enhanced biohydrogen generation from food waste.