Super Fungi! How Much Do You Owe the Fungi for Your Shopping Basket? David Moore

Superstore - super fungi! How much do you owe the fungi for your shopping basket? David Moore

We all have different attitudes to fungi, but do you by brewers. The yeast uses the same chemistry of know just how much, every hour of every day, we ethanol fermentation for both industries: C6H12O6 all depend on fungi and fungal products? Or how → 2 C2H5OH + 2 CO2. However, for the brewer the much fungi contribute to our everyday retail key product is ethanol; for the baker the key experience? Let’s take a walk around the nearest product is the carbon dioxide. Bread structure superstore and look at the fungal contribution to depends on the gluey properties of the wheat the goods on sale. gluten protein. Carbon dioxide gas is trapped into bubbles by the gluten, and the bubbly structure of the dough is turned into the open structure of Mushrooms. Mushrooms are a high-quality food bread when cooked. For hundreds of bread source with protein typically 20-30% of dry recipes see: http://www.cookitsimply.com/category- matter, and containing all the amino acids that are 0020-0e1.html essential to human nutrition, low-fat content, and useful B vitamin content. Fungi are easily digested and their cell walls provide a good source of Beers and Ales. These are products of the dietary fibre. Most important of all they have no fermentation of sugars from cereal grains by the cholesterol. European mushroom farms cultivate yeast called Saccharomyces cerevisiae. All ales, Agaricus bisporus. Oyster and Paddy straw beers and lagers are made from malted barley mushrooms are cultivated in Asia; though in Japan mashed into hot water and boiled with hops to and China Lentinula (shiitake in Japanese or add bitter flavours to the beer. The yeasts used for shiangu in Chinese) is a major crop. making ales tend to form froth and grow on the top of the mix. Lager yeasts ferment at the bottom

of the tank and belong to the closely-related Fresh meat and dairy products. Our farm animals species Saccharomyces carlsbergensis. (See: are kept alive by the fungi in their digestive http://www.howtobrew.com/). systems to cope with otherwise indigestible fibres in grass. The gut of ruminants (like cattle) contains large chambers that form a fermentation vessel Fuel alcohol. Ethanol is also used as a chemical where the microbes grow. The fungi concerned feedstock and as an automotive fuel when up to are known as ‘obligately anaerobic chytrids’; they 10% ethanol by volume is mixed with petrol. Yeast digest lignin and carbohydrate and pass some fermentation of agricultural wastes is most often nutrients on to methanogenic bacteria. The two used. Together, the USA and Brazil produce 85% of work together, carrying out a more efficient the world’s fuel ethanol. Most of the US ethanol is fermentation process, generating a larger produced from maize and other cereals, while microbial community, and greater benefit to the Brazil uses sugar cane. The US produces most fuel host animal when it digests the microbes. ethanol; over 100 billion litres were produced worldwide in 2017, of which 60 billion litres was

produced in the US, 27 billion in Brazil and 5.3 Bread. Leavened bread is a product of the billion in the EU (https://www.afdc.energy.gov/data/). fermentation of sugars from cereal grains by the yeast Saccharomyces cerevisiae. This is known, not surprisingly, as Baker’s yeast in this industry, Wines. Vitis vinifera grape juice is obtained by although in the old days it was supplied to bakers crushing grapes; the grape juice is referred to as

production of cured and fermented meat Marmite. Brewing beers produces a vast amount products. Chopped meat (including beef, goat, of live yeast as a ‘waste’ product and these horse, lamb, pork, poultry, and/or venison) is brewery wastes are converted into flavourings, mixed with minced animal fat, cereals, herbs, diet supplements and ‘yeast extract’ products with spices; this mixture gives the salami sausage its brand names like Marmite, Meridian Yeast Extract typical marbled appearance when cut. Salt is and Australian Vegemite, Swiss Cenovis, and the added and the mixture ferments for a day before German Vitam-R. In the first stage of Marmite being stuffed into a casing, covered with a production, the brewer’s yeast is broken down to suspension of the Penicillium nalgiovense starter proteins and soluble amino acids; this mixture is culture, and finally hung to cure. As the fungus filtered, secret flavourings (in a vegetable juice grows over the sausage and into the meat it concentrate), vitamins and spice extracts are imparts flavour and protects against spoilage by added, and the product is ready for packaging other undesirable species of yeasts, moulds and (https://www.marmite.co.uk/). bacteria.

Quorn. Mycoprotein™ is the name for a food Fizzy drinks. Apart from alcohol (ethanol), the product made from a strain of the filamentous single most important pure chemical produced by fungus Fusarium venenatum. The fungus is grown fermentation is citric acid (global production is on food-grade glucose as the carbon source in a 45 about 1,600,000 tonnes annually). This is a weak m tall airlift fermenter. Mycoprotein typically 6-carbon organic acid that is a naturally occurring contains 44% protein, 18% dietary fibre and only component of metabolism in almost all living 13% fat (the values for beef are 68%, 0% and 30% things. The structure of the molecule confers a respectively), and raw mycoprotein contains no variety of properties that make citric acid useful in cholesterol. The sole use for mycoprotein foods, effervescent soft drinks, and phar- currently is as the primary ingredient of the maceuticals as a pH buffer, acidifier, preservative Quorn™ range of ‘meat-alternative’ products. See and/or metal ion chelator. The standard (https://www.quorn.com/). fermentation production method uses Aspergillus niger on a medium containing 15% sugars. Under

optimal conditions, fermentation is complete in 5 Cheese. Cheese is a solid or semisolid protein food to 10 days (https://ihsmarkit.com/products/citric-acid- product manufactured from milk. Before the chemical-economics-handbook.html). advent of modern methods of refrigeration, cheese manufacture was the only method of preserving milk. Basic cheese making is a bacterial Fruit juices. Fungal enzymes are used extensively fermentation, but there are two important in production of non-effervescent fruit juices to processes to which filamentous fungi contribute. maximise the yield of extracted juice. For example, These are the provision of enzymes (80% from processing apples utilises ‘macerating enzymes’,

In the pharmacy. Fungus-produced penicillin is Soy sauce, tempeh and other food products. still an important antibiotic, but most antibiotics Fungi are used for processing several food that we use today originate from bacteria (grown products that enjoy large markets in Asia, and in large fermenters). Fungi produce some other traditional oriental cooks have applied a variety of crucial pharmaceuticals, though: for example, the fermentation techniques to the seeds of soya, rice fungal product called cyclosporine, which and other crop plants in ways like the suppresses the immune response in transplant fermentation techniques that traditional patients to avoid organ rejection. Mevinolin is a occidental cooks have applied to dairy products compound produced by the fungus Aspergillus and meat of various animals. Fermentation of soy terreus which is the basis of the statins. These are beans with filamentous fungi (particularly used to reduce cholesterol levels; high cholesterol Aspergillus, Actinomucor, Mucor, or Rhizopus spp.) is a risk factor in cardiovascular disease, stroke and is the basis for production of a range of foods, several other widespread illnesses. Since their including sufu (fermented tofu), soy nuggets, introduction in the late 1980s, statins have tempeh, miso and ang-kak (red rice). Bacterial become the most widely prescribed cholesterol fermentation is used to produce natto and soy lowering drugs in the world. Fungi also produce yoghurt. Non-fermented soyfoods include compounds known as ergot alkaloids, which were soymilk, tofu, soy sprouts, yuba (soymilk film), the first antimigraine drugs available. Although okara (soy pulp), vegetable soybeans, soynuts and these can be synthesised, fermentation remains toasted soy flour. the most cost-effective production method. Steroid compounds are among the most widely

marketed products of the pharmaceutical industry Chocolate and coffee. All chocolate products are and most of the steroids in clinical use today are derived from cacao seeds formed in large pods on modified by fungi and/or fungal enzymes during the trunks of the evergreen cacao tree manufacture. Using fungi and their enzymes (Theobroma cacao). Each pod contains about 40 enables compounds to be made that would seeds (the cocoa ‘beans’, though they are not true otherwise be very difficult, impossible, or just too beans) embedded in a fleshy pulp. Pod contents expensive to produce by direct chemical synthesis. are scooped out and pulp and seeds piled in heaps Manufactured steroids are used for many ‘over- for several days, during which they undergo a the-counter’ remedies as well as ethical natural microbial fermentation by a succession of (prescription-only) therapies. Common uses yeasts and bacteria. This liquefies the pulp and include anti-inflammatory, immune-suppressive, imparts the flavour of chocolate to the cocoa diuretic, anabolic, contra-ceptives and seeds that are left behind. Unfermented cacao progesterone analogues. Manufactured steroids seeds do not have any chocolate flavour. Coffee are also used to treat some cancers, osteoporosis undergoes a similar fermentation, and for similar and adrenal insufficiencies (the adrenal glands reasons. Several species of the bushy tree Coffea produce natural steroid hormones), for avoidance produce cherry-like fruits that contain two seeds of coronary heart disease, as antifungal or anti- (the coffee ‘beans’). Harvested fruits have most of obesity agents, and some steroids can be used to the berry flesh removed in water, then the coffee prevent and treat infection by HIV. seeds (‘beans’) are fermented in large water containers to dissolve away a parchment-like film Clothing: enzymes for fabric conditioning and of tissue that surrounds them. When complete, processing. Despite the successful emergence of

This article is one of a number invited as part of the MiSAC 50th anniversary celebrations. The articles are written by experts and are both up to date and relevant to microbiology in schools. MiSAC is grateful to all contributing authors. Copyright © MiSAC 2019. 3 synthetic fibres such as nylon and polyester, a  Fungal biotechnology: great many of our fabrics are still made from the http://www.davidmoore.org.uk/21st_Century_Guidebook_t natural fibres cotton (cellulose), wool and silk o_Fungi_PLATINUM/Ch17_00.htm  Soy sauce and other fermented food products: (both protein), all of which can be processed in http://www.davidmoore.org.uk/21st_Century_Guidebook_t various ways with natural enzymes. The fabric o_Fungi_PLATINUM/Ch17_25.htm processing with which we are most familiar results  World of Fungi: from the inclusion of fungal enzymes in detergents http://www.davidmoore.org.uk/index.htm and associated fabric conditioners used for clothes washing. Some of these enzymes are derived from bacterial sources, but many are fungal enzymes. AUTHOR PROFILE Enzymes are also used during manufacture of textile products to improve the properties of the Dr David Moore was formerly Reader in fabrics. Fungal cellulase enzymes remove loose Genetics in the Faculty of Life Sciences at fibres from cotton fabrics more efficiently and Manchester University. His research interests more gently than mechanical methods of finishing. were in fungal physiology and mutant isolation Many traditional finishing processes in the wool and linkage mapping in Coprinopsis cinerea. industry require chemicals that cause pollution. David has held a number of senior positions in Fungal proteolytic enzyme treatments achieve a the British Mycological Society including that variety of finishing effects for woollen products of President and was creator and webmaster with minimal environmental impact. of its web site. He was instrumental in establishing the society’s outreach and More information education work in schools, science fairs and RHS shows for which he has received the  Exploiting fungi for food: society’s awards. David is the author of a http://www.davidmoore.org.uk/21st_Century_Guidebook_t o_Fungi_PLATINUM/Ch11_00.htm number of books on mycology.