Is that Bioplastic in your Solid Waste Stream? Interview with Robert Dombrowski, Nanoview Associates LLC by Willi Paul

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Is that Bioplastic in your Solid Waste Stream? Interview with Robert Dombrowski, Nanoview Associates LLC by Willi Paul

Image Source: Bio-Polym Blog

There are several main classes of Biodegradable plastics that are used in applications at this time. These classes of materials are:

• Biodegradable – breakdown by microbes / bacteria
  
• Compostable – these plastics can be placed in compost conditions to breakdown without interfering with the production of usable compost.
  
• Hydro-biodegradable – these plastics breakdown in the presence of water.
  
• Photo-biodegradable – these plastics breakdown when exposed to ultraviolet light / sunlight.
  
• Bioerodable – these materials erode or breakdown when placed in the body – they are usually used in biomedical implants. Biodegradation occurs only if all fragmented plastic residues are consumed by microorganisms as food and are used as their energy source. The theoretical final breakdown products in biodegradation being carbon dioxide, water and cell biomass.

What are bioplastics? What material(s) came before these?

Bioplastics are polymeric materials (polymer – material composed of molecules containing long chains whose backbones contain carbon atoms) derived from renewable biomass sources rather cthan from petroleum. Examples of these biomass sources are polymerized soybean oil, starches (corn, potato, tapioca, etc.), seaweed & bacterial fermentation of agricultural waste. Not all
bioplastics are designed to biodegrade. Even though the existence of many bioplastics have been known for many years, until recently most consumer & industrial packaging were made of polymeric materials derived from petroleum (i.e. polyethylene & polypropylene). These petroleum derived materials do not degrade or biodegrade or they do so at extremely slow rates
in the environment.

Describe how naturally occurring microorganism such as bacterial, fungi and algae provide the engine for degradation?

The bacteria, fungi and algae use the carbon based chains in the biodegradable materials as food & sources of energy. Most bioplastics contain polymer chains that are composed of “sugar-like” units which are “ideal” food & energy sources. The polymer chains are consumed by an array of natural chemical reactions within the various organisms.

How do you see the impact of carbon in the degradation process? Are you calculating this impact in a footprint assessment?

I am not aware of any extensive scientific studies of how biodegradation impacts the carbon footprint of packaging in the solid waste stream. I imagine that the use of bioplastics is some - what carbon neutral. Example: Agricultural feedstock – production of bioplastics – composting – growth of more agricultural feedstock. It seems that this can be looked at as a “carbon neutral” packaging production – usage – composting loop. The only other question would be how to “collect” or “harvest” the carbon dioxide produced by future municipal level composting facilities for useful purposes.

In simple terms, discuss the role of sunlight and water in the breakdown of plastics.

Sunlight and water help promote the biodegradation of most biodegradable packaging. Both factors promote hydrolytic, oxidative & enzymatic reactions that break susceptible linkages in the polymer chains of the packaging material which reduces the average molecular weights of the polymer chains. Below a certain molecular weight bacteria start to consume the material &
the material loses its mechanical properties resulting in degradation to polymer fragments. Complete biodegradation occurs if all fragmented residues are consumed by microorganisms as food & their energy source. The ideal biodegradation end products would be carbon dioxide, water & cell biomass.

Sunlight / ultraviolet light is even more of an important factor in the degradation of what are termed “Oxo-biodegradable” materials. These materials are usually petroleum based polymers that contain metal based catalysts that are activated by sunlight / ultraviolet light. Once these catalysts are activated they start chain cleavage reactions that reduce the chain molecular weights
& this reduction in molecular weight eventually leads to bacterial consumption & biodegradation. There are many potential environmental problems with the use of these Oxobiodegradable materials over bioplastics.

Define “environmentally friendly.”

My definition of environmentally friendly with respect to the biodegradation of bioplastics based packaging is that the degradation process will have no detrimental effects on the environment – no toxic breakdown products including the non-production of fine polymer dusts, total degradation to carbon dioxide, water & cell biomass (all natural components) & production of high grade compost for landscaping & agricultural production.

What are some of your recent successes in nanostructural analysis and productization?

In recent years I have been involved with the micro / nanostructural characterization of Nanobiomaterials at the Medical Device Concept Laboratory - New Jersey Institute of Technology (Newark, New Jersey). These Nano-biomaterials are used in the production of electrospun bioerodable scaffolds (similar to non-woven fabrics) that are meant to be implanted into the human body. The ability of the structures produced to bioerode is critical to allow the scaffolds to incorporate into the human body with minimal immune response.

The scaffolds are produced by spraying a liquid polymer stream into an electric field resulting in the production of fibers with diameters on the nano level. The resulting scaffolds are then seeded with stem cells to produce semi-natural human body component replacements. The initial goal was to produce replacement spinal discs.

Much micro / nano characterization is needed to produce structure – property models that help explain to researchers how the materials perform in the desired final applications. This way material compositions & manufacturing processes can be adjusted to produce materials / structures that will have the desired final performance properties in the body. The micro / nano characterization studies are carried out using analytical polarized light microscopy (PLM), laser scanning confocal microscopy (LSCM), field emission scanning electron microscopy (FESEM) & Atomic Force Microscopy (AFM).

Do you work with bioreactor technology? How do you scale-up your processes?

I do not directly work with bioreactor technology in my Biodegradable / Bioerodable Materials consultancy practice at Nanoview Associates LLC There are classes of biodegradable materials that are produced using bioreactor technology. One of these biopolymers is poly-3-hydroxybutyrate (PHB) - member of a broader class of biopolymers called polyhydroxyalkanoates (PHAs). PHB is a polyester produced by certain bacteria processing glucose or starch. Its characteristics are similar to those of the petroleum
derived polypropylene.

In the 1980s & early 1990s the British company Imperial Chemical Industries (ICI) developed a process that used bacteria genetically modified to produce PHB within their cells. The PHB production process was carried out through fermentation in bioreactors. The resulting classes of commercial materials were sold under the tradename of Biopol. In 1993, ICI transferred its biological division to Zeneca which continued to develop the PHAs under the Biopol tradename. Zeneca then sold its Biopol assets to Monsanto in the mid 1990s. In 2001, an American company, Metabolix, Inc. acquired the Biopol assets from Monsanto. Metabolix is developing
trans-genic approaches to the large scale manufacture of PHAs through fermentation & agricultural biotechnology.

With all the mergers & takeovers that have occurred in the Specialty Chemical & Biotechnology industries over the last several decades the Biopol tech transfer saga is not uncommon. Hopefully, good & sound “Green” materials technologies eventually winds up in the right organizations that will see their potential & effectively carry out their commercialization & promote their wide spread usage.

Please critique the current landfill or recycling operation in the US. What needs to improve in terms of disposal and degradation of plastics?

Today the majority of solid waste is buried in landfills. Not much degrades effectively in modern landfills & a large amount of methane is produced. There have been studies in which they excavated decades old newspapers out of landfills that could still be read today. The environmental benefits of biodegradable packaging are not realized in the landfill environment – the bioplastics based packaging is entombed.

To fully utilize the environmental benefits of biodegradable packaging we need to develop a municipal level composting infrastructure. This idea is not new – when I was Research Associate / Head of Microstructural Characterization at Novon Products (Morris Plains, New Jersey) in the early 1990s I served as a member of a Biodegradable Packaging Consortium comprised of members from industry, academia, the Federal government, the military & NGOs that explored such an idea. We had a test municipal composting facility in Haddonfield, New Jersey where biodegradable starch based / starch – known biodegradable synthetic blends produced by Novon Products were placed in compost to monitor their biodegradation. Municipal level composting based on state-of-the-art technology I feel is the future for reaping the maximum environmental & societal benefits of using bioplastics based biodegradable packaging in the solid waste stream.

NOTE: Novon Products was Warner Lambert’s (now Pfizer) effort to produce biodegradable starch based / starch – known biodegradable synthetic blends for $Billion Consumer Packaging & Medical Consumables markets.

Robert Dombrowski, Email Communiqué –

“I have been involved with Biodegradable materials - packaging since the early 1990's. At that time I was Research Associate / Head of Microstructural Characterization for Novon Products. Novon Products was Warner Lambert's (now Pfizer) effort to produce biodegradable starch based materials / starch - know biodegradable synthetic blends for $Billion Packaging & Medical Consumables markets. I have continued this work since that time - I have extensive knowledge of Biodegradable Materials Science, Characteriztion, Degradation / Biodegradation Mechanisms, Materials / Biodegradation Testing, Post Consumer Processing / Handling - Breakdown Fates & Policy.

I am the President / Principal Scientist of Nanoview Associates (NVA) LLC NVA is a Scientific / Technical Consultancy with a very large portfolio of advanced areas of consultancy expertise & services - main expertise areas: Biodegradable Materials / Packaging & NanoBiotechnology.”

Connections –

Robert T Dombrowski, President / Principal Scientist
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Nanoview Associates LLC
P.O. Box 6190, East Brunswick, NJ 08816