Biotransformation of agro-industrial waste to wealth in Africa through mushroom farming

Discarding Waste in open drainages, water bodies and unauthorized dumpsites is a common practice in Africa that is deleterious to the global ecosystem. Global warming, flooding and land encroachment are direct impact of these actions. Therefore, a proposed eco-friendly solution to efficient waste management in Africa is “Mushroom Farming”. The region between Latitude 6.43–7.95°N and Longitude 2.88–5.24°E (Nigeria) was the research focus. Mushroom samples were collected, identified, coded and geo-tagged in the field, while Laboratory analyses and mushroom cultivation was conducted in NIHORT and University of Ibadan. The result showed that postharvest waste (rice straw) was best for spawning (Ek1-8→23days, LA1-8→21days, OG1-8→20days, and OY1-8→22days), while agro-waste from Gliricidium sepium facilitated early pin head emergence (26days) and fruiting (28days). Also, agro-waste from Cedrela odorata facilitated early maturation (3days after fruiting), and those from Mangifera indica, G. sepium and C. odorata, improved yield (9.05g), pileus size (4.24g) and dry matter (3.01g), respectively. The Laboratory analyses showed that LA1-8 had the best N2, Na and Ca contents (13.59, 70.49 and 61.90mg/100g, respectively), while fat, fibre and carbohydrate contents were highest in samples from EK1-8 (6.60%), OS1-8 (25.13%) and OG1-8 (54.23%), respectively. Mushroom farming is the key to efficient transformation of waste to wealth in Africa.

and total conservation of endangered mushroom species. As such, a better understanding of the 95 nutritional and physiological requirements of wild edible mushrooms will serve as a pivotal for 96 the proposed waste management strategy that should be developed in Africa.

Spawning on agro-industrial and market wastes
136 Spawn production was aided by the method of Adenipekun et al. [2]. Rice straw, sawdust, cotton 137 waste and wheat bran were soaked in water for 1hr, while sorghum and maize grains were soaked 138 for 24hrs (to remove chemical residue) after which they were drained and air dried for 4hrs (The 139 substrates were listed in Table 7). For small scale spawn production, 500g of nutrient supplements 140 (sorghum or maize grain) were weighed out, mixed with 1% calcium carbonate (CaCO3) and 1kg 141 spawn substrate (Rice straw/Sawdust/Cotton waste and wheat bran in a ratio of 2:1, respectively). 142 The final substrate mixture was loaded into 350cm 3 (13 x 8 x 8) sterile bottles, covered with 143 aluminum foil, and autoclaved at 760mmHg and 121 o C for 15mins. The sterilized spawn substrate 144 was inoculated with pure culture of Auricularia mushrooms and incubated at 25±2ºC for three (3) 145 weeks. For large scale spawn production, the substrate mixture was made up to 10kg and stored 146 in heat resistant polypropylene bags (20cm x 12cm dimension). The bags were tightly secured 147 with cotton strings and sterilized at 100 o C for 4hrs. The procedure for inoculation and incubation 148 were similar to that of the small scale spawn production method. 149

150
The pruned branches were cut to a standard size of 40cm using a chain saw. Holes were drilled on 151 the logs using a manual hand drilling machine (Specification: width = 8mm, depth = 20-30mm 152 and distance apart = 40-60mm apart). The drilled logs were covered with sterile polyethylene bags 153 prior to inoculation to avoid contamination. 154   The crucibles containing the samples (m1) were heated at a steady temperature 199 (105ºC) and constant pressure (760mmHg) in a well ventilated hot air oven.  Table 8. Also, cotton waste from Bodija market was 338 beneficial in reducing the spawn period of mushroom samples collected from Ondo (OD1-8 = 339 23days) and Osun (OS1-8 = 20days). The quality of spawn substrate was rated as Rice 340 straw>Cotton waste>Saw dust (Table 8). 341

419
The best substrate for spawn production, pin head emergence and production of mushroom fruiting 420 bodies was Gliricidium sepium with a short time frame of 22days for spawn production, 26days 421 for pin head emergence, and 28days for the Auricularia mushrooms to produce fruiting bodies, on 422 the average (Table 15). The best substrate that supports early harvesting of mushrooms was C. 423 odorata with an average value of 3days. The best substrate for yield improvement, enhanced size 424 of mushrooms produced and increase in dry matter acquisition were M. indica (9.05g), G. sepium 425 (4.24g) and C. odorata (3.01g), respectively (Table 15). 426 , who stated that most fungi are able to synthesize their own vitamins. There was 499 no significant difference in the protein and ash contents of all the Auricularia mushrooms 500 cultivated in the present study irrespective of the substrates used to grow them and the location 501 where they were collected from. The highest fat content was obtained from mushrooms samples 502 from Ekiti State, while the highest crude fibre content was from Osun samples, and carbohydrate 503 composition was more in mushroom samples from Oyo, Lagos and Ogun States. This 504 observation was synonymous to that made by Okhuoya and Ayodele [25], who noted that fresh 505 mushrooms contain relatively large amounts of carbohydrate and fibre ranging from 51 to 88% 506 and 4 to 20% (dry weight), respectively, for the major cultivated species. 507

508
The generation of profitable income through wastes disposal and waste wood management is a 509 more lucrative aspect for rapid economic growth that has not yet been fully exploited globally. 510 Cultivation of mushrooms on industrial wastes, waste woods, agricultural wastes or wastelands 511 can foster rapid biological cleaning of the environment, create more arable farmlands for the 512 cultivation of other economically important food crops, increase the option of nutrient availabity 513 to man and animals, promote wealth generation from waste, and finally, reduce risk of 514 mycotoxicosis through the consumption of poisonous mushrooms reported globally. The