Production of Shiitake Mushroom on Tree Waste

0881-B2

Arun Arya^[1] and Chitra Arya

Abstract

Forest waste like leaves and wood can be utilized in a better way than burning as fuel. Production of mushrooms as a good quality protein from agro and forest wastes is a suitable alternative. The forest floor can be cleaned and leaves can be utilized for production of mushrooms. The sawdust produced in sawmills is wasted. An alternative approach to use this in mushroom cultivation is proposed.

The shiitake mushroom (Lentinus edodes (Berk.) Pegler) is liked due to the presence of unique flavor-enhancing compounds. The anti-tumour properties of Lentinus are attributed to the presence of polysaccharide Lentinan and amitanin. A composition for treatment of AIDS is prepared from the mycelium of Lentinus. Shiitake has been produced for hundred of years in the orient primarily by growth on hardwood logs. Relatively recent developments, however, have provided growers with the option of producing shiitake on supplemented sawdust. The advantage of producing mushroom on sawdust includes less time required. The major disadvantage, however, is the relatively high initial investment cost.

A substrate was used consisting of 800 g of sawdust, 100 g of wooden wool (Tectona grandis, Acacia arabica, and Terminalia catappa), and 100 g of pearl millet (Pennisetum glaucum). The pH of the substrate was adjusted to 6.0. Warty growth appeared on the 140th day, after 160 days button-like structures were seen on synthetic logs and after 170 days fruiting bodies were produced. Biological efficiency was 45%. Biological efficiency can be further increased by supplementing the sawdust with yeast and maize meal (de-oiled Zea mays extract).

Introduction

Mushrooms are nutritionally functional food and a source of physiologically beneficial and nontoxic medicines (Wasser and Weis 1999). ‘Soma’ the divine drink is supposed to be obtained from the mushrooms. RigVeda says Apamiva bhavatu rakshasa sah, 9:85, which means with the help of ‘soma’ we may be free from diseases, and demons. Mushrooms find their place in traditional folk medicine throughout the world since ancient times. In present scenario this study may help to develop strategies to produce large scale edible proteins, which will solve the problem of hunger and malnutrition in African and developing Asian countries.

In India, button mushroom still constitutes 85-90% of total mushroom production, followed by 15-19% oyster mushroom. Other cultivated mushrooms are not favorite of growers due to unavailability of suitable technology. However, varied agro-climatic conditions and availability of a variety of forest and agro-wastes within this country offer great opportunities for cultivating a variety of mushrooms. There is an immediate need to diversify the mushroom portfolio of the country. Cultivation of Lentinus is usually practiced by inoculating wooden logs and it takes 6 months to 2 years to produce sporophores. An economical plastic bag method is developed which yielded good fruit bodies in lab conditions.

Lentinus edodes (Berk.) Sing. commonly known as Shiang-gu in China and Shiitake in Japan, is a white rot wood decay fungus that naturally inhabits the dead wood of many hard wood tree species in Asia. The name of the mushroom is derived from a Japanese tree named Shiia, which bears this mushroom. A famous Chinese doctor Wu Rui during Ming dynasty (1368-1644) wrote that, the Lentinus mushroom was capable of generating stamina, curing cold, improving blood circulation and lowering blood pressure (Jones 1995). Shiitake has been credited with antitumor, antiviral, hypolipidemic, hypocholesteralemic and antibiotic properties. The antitumour properties are attributed to the polysaccharides Lentinan (Chihara et al. 1970) and emitanin (Yamamoto and Ikegawa 1980). Extracts from L. edodes was shown to prevent viral infection in both plants and animals. A composition for treatment of AIDS was prepared from the mycelium of Lentinus (Hobbs 1995).

Present paper reports cultivation of Lentinus edodes on forest tree wastes. Synthetic logs were prepared from saw dust of Tectona, Terminalia and Acacia woods.

Material and methods

A culture of L. edodes OE-2 was procured from National Center for Mushroom Research and Training (NCMRT) Solan, India. As potato dextrose agar medium supported poor growth a PDA medium supplemented with yeast powder (0.1%) was used to maintain stock cultures. Spawn was prepared by adding sawdust 10g, pearl millet grains 10g, yeast extract 0.1%. Bavistin 35 ppm, distilled water 50ml. Autoclaving was done at 15 lbs p.s.i. for 1h. The inoculated flasks were incubated at 20° C for 15 days to get good quality spawn. A small bit of 15 d old mycelial culture was inoculated in spawn flasks under aseptic conditions and incubated at 18±2° C for 21 d.

A substrate was used consisting of saw dust 800g, wooden wool 100g, pearl millet 100g, brewer’s yeast 1g Bavistin 100 mg. Saw dust was obtained from a local saw mill which consisted of Tectona grandis, Acacia arabica and Terminallia catappa. pH of the substrate was adjusted to 6.0. Polypropylene bags (30 × 45 cm) were filled with substrate and autoclaved at 15 lbs. p.s.i for 1h. Next day spawn was inoculated by making 4 holes in the substrate 4 cm deep. Polypropylene bags were incubated at 20° C in darkness. Saw dust substrate was completely covered with white fluffy mycelium after 120 days.

Results and Discussion

Growth of Rhizopus stolonifer and Trichoderma viride were observed in bags without Bavistin. The polypropylene bags were cut and solid mass(synthetic log) was placed in a chamber on a raised platform. Humidity was maintained 90-95%.

C: N ratio which is different in various plant tissues is known to be an important factor in influencing the rate of decomposition (Flaig 1964). On ‘0’ day the C:N ratio of the substrate was 300:1 on 140 day the ratio was 190:1 and it became 80:1 after 170 days. Biodegradation of lignocellulosic substrate by fungi is studied by numerous investigators. Recycling of nitrogen by the fungi through autolysis and reuse and action of diazotrophs have been suggested (Levi et al. 1968, Balaji et al. 1999)

Warty out growths were seen after 140 days. pH of the substrate changed from 6.0 to 5.5 After 160 days young buttons were observed which were reddish brown in colour. After 170 days of spawning these young buttons opened to form umbrella like pileus. pH of the substrate was 6.0 at this stage. Each mushroom had about 2.7-cm long stipe and 7.8 cm dia pileus. The margin of basidiocarps were curved inside. The basidiocarps were more harder in texture than Agaricus bisporus (Button mushroom). Results are recorded in Table 1.

Table 1 Data* (mean) showing cropping pattern of Lentinus edodes on mixed saw dust.

• Average of 3 replicates in two trials.

  ¹ First flush

  ² Second flush

Good yield (45% BE) was obtained at 15⁰ C on sawdust without any supplement indicates that this species can also be exploited commercially in our country in colder months. More studies like nutrient supplementation and improved cultivation practices are however needed to further improve the yields on industrial scale.

Most of the Lentinus spp. are lignolytic in nature and about 14 species have been reported from all over the world. L. kauffmanii and L. lepideus are regarded as destructive parasite of wood. L. edodes was grown in laboratory on hardwood saw dust and different strains of this mushroom can be cultivated at low temperature (10-22° C). L. squarrosulus Mont. is collected and consumed by local people in Nigeria. It is easy to grow on wheat and paddy straw compost (Upadhyay and Rai 1999). Ray and Smajpati (1997) reported requirement of vitamin thiamin for the mycelial growth of L. squarrosulus and L. polychrous, spraying of this vitamin on substrate may yield better results.

Cost of production of Lentinus was Rs. 55/= kg.The expenditure on building, labour and electricity were main expenses besides cost of saw dust for synthetic logs and fungicides, polpropylene bags etc. Being a medicinally important mushroom the selling cost is estimated to be Rs. 100/= approximately. The production cost is inversely proportional to the size of the unit. In other words, as the amount of mushroom production will increase the production cost per kg of mushroom will decrease. The above data clearly reveal that investment in Shiitake mushroom unit is economically viable.

Acknowledgements

We thank Dr. R.N. Verma, Director NCMRT, Solan for providing the culture of Lentinnus edodes and Prof. G. P. Senan, Head of Dept. of Botany, M. S. University for providing necessary laboratory facilities. Financial assistance provided to C.A. in form of PDF by M. S. University is gratefully acknowledged.

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