Are there bacteria that "eat paper" in nature?

When I saw a netizen asking "Are there bacteria that can 'eat paper'?", I couldn't help but think of the world of microorganisms, which is a huge and complex field that covers many tiny organisms, including bacteria, viruses, fungi, protists, microscopic algae, etc. These microorganisms are widely distributed on the earth, in large numbers, and are closely related to human life.

So, of course there are bacteria in nature that can "eat paper", and they are a large group. In fact, the so-called "eating paper" is biodegradation. There are many bacteria in nature that can degrade cellulose. They can decompose cellulose through specific enzymes, but not all bacteria that can decompose cellulose will feed on paper. Let's talk about paper degradation step by step.

01. Composition of paper

To degrade paper, we must first understand the composition of paper. Paper is made of cellulose, which has a very simple chemical composition. It is a linear polymer composed of two layers of β-D-glucose linked by β-1,4-glycosidic bonds, with a high degree of polymerization (usually 4000-8000 glucose molecules connected in series, with a molecular weight of 200-2000KDa).

02. How to degrade paper?

Once we understand the composition of paper, we can degrade it. The key to degrading paper is cellulose degradation, and cellulase can degrade cellulose into glucose.

There are a large number of cellulose-degrading strains in nature that can be used to produce cellulase, including thousands of fungi, bacteria, actinomycetes and other microorganisms that can degrade cellulose.

03. What is the specific degradation process?

There are generally two ways in which paper can be degraded:

1. First the outside, then gradually develop inwards, mainly bacteria.

Bacteria generally adhere to cellulose fibers and proliferate from the surface of the fibers to the inside. The cellulose is dissolved at the contact points, leaving jagged marks on the fiber surface. If the fibers destroyed by bacteria are swelled by a certain solution, the fibers will be pulled up and destroyed due to the lack of uniform swelling of the primary and secondary walls, and they will be easily decomposed.

Common bacteria:

Aerobic bacteria : Cytophaga; Cellvibrio; Cellulomonas

Anaerobic bacteria : Clostridium omelianskii; C. thermocellulaseum;

2. Destruction from the inside out, mainly fungi and actinomycetes

Mold is linear and its degradation of cellulose is concentrated at the ends of the fibers. It continues to grow, digesting cellulose from the inside out, gradually breaking down and destroying the fibers.

Common fungi: Aspergillus ; Trichoderma ; Penicillium ; Stachybotrys ; Thermomyces .

Note: All the above are fungal genera. As you know, in biological classification, the genus is the second to last category, and under it there are species. Therefore, the number is extremely large. Take Aspergillus as an example, there are probably hundreds of species of Aspergillus. [References]

Biodegradation of lignin in a compost environment: a reviewAnaerobic biodegradation of the lignin and polysaccharide components of lignocellulose and synthetic lignin by sediment microflora

Mechanical, moisture absorption, and biodegradation behaviors of bacterial cellulose fiber-reinforced starch biocomposites

ps: This article draws heavily on the research of "Screening and Characterization Research of Cellulose Degrading Bacteria_Fan Yanli", please delete if infringed.