Method for Zero-Waste Circular Economy Using Worms for Plastic Agriculture: Augmenting Polystyrene Consumption and Plant Growth

Abstract

Polystyrene (PS) is one of the major plastics contributing to environmental pollution with its durability and resistance to natural biodegradation. Recent research showed that mealworms (Tenebrio molitor) and superworms (Zophobas morio) are naturally able to consume PS as a carbon food source and degrade them without observable toxic effects. In this study, we explored the effects of possible food additives and use of worm frass as potential plant fertilizers. We found that small amounts of sucrose and bran increased PS consumption and that the worm frass alone could support dragon fruit cacti (Hylocereus undatus) growth, with superworm frass in particular, supporting better growth and rooting than mealworm frass and control media over a fortnight. As known fish and poultry feed, these findings present worms as a natural solution to simultaneously tackle both the global plastic problem and urban farming issue in a zero-waste sustainable bioremediation cycle.

Worming the Circular Economy for Biowaste and Plastics: Hermetia illucens, Tenebrio Molitor and Zophobas morio

“…T. molitor showed increased consumption of PS when they are of lower density and at the optimal ambient temperature at 20 to 30 °C [46,47]. Rates of 1.40 mg of PS consumed per day for each gram of worm present could also be augmented by the addition of sucrose or bran to 3.55 mg and 2.14 mg of PS consumed per day for each gram of worm present, respectively [36].…”

“…A parallel study normalizing by per gram of worm, reported the rate to be at 1.04 mg of PS was consumed per day for each gram of worm. With the additions of small amounts of table sucrose or bran, the rate increased to 1.90 mg and 1.79 mg of PS consumed per day for each gram of worm present, respectively [36].…”

“…While plastics do not occur naturally, nature has a solution to man's artificial problem in the insects. These biological expertise include: Tenebrio molitor [36][37][38], Zophobas morio [35,36,39] and waxworms (Galleria mellonella L.) [40,41] to utilize PS and PE for mineralization [35,36,[39][40][41] as a carbon source. Fully digested, their frass can be utilized as natural fertilizers.…”

“…2. To decrease the microplastic content excrement by having multiple layers of worm feeding chambers where lower levels of worms will consume the frass and reduce microplastic and monomer content [36]. 3.…”

Waste to value: Global perspective on the impact of entomocomposting on environmental health, greenhouse gas mitigation and soil bioremediation

“…Similar results were achieved using Aqularia malaccensis trees whereby application of ICOF increased the growth rate by 9–15 % compared to conventional organic fertilizers ( Mohamad Amir Hamzah et al, 2021 ). Furthermore, application of frass fertilizers generated by superworms and mealworms improved the rooting and growth performance of Hylocereus undatus , but the performance of superworm frass was superior to that of mealworm frass ( Gan et al, 2021 ).…”