**Table 6.**

*Effect of SMS on seedling growth of chili.*

*Emerging Contaminants*

**256**

**Aqueous SMS conc. (%) (w/v)**

20 40 60 80 100 Control

**Table 5.**

*Effect of SMS on seedling growth of tomato.*

**Shoot** 3.182 ± 0.038 3.622 ± 0.031 4.446 ± 0.094 4.048 ± 0.095 2.252 ± 0.258 1.259 ± 0.011

**Fresh weight (g)**

**Root** 0.828 ± 0.014 0.898 ± 0.011 1.108 ± 0.024 1.012 ± 0.025 0.658 ± 0.072 0.301 ± 0.009

**Whole plant** 4.010 ± 0.048 4.520 ± 0.043 5.554 ± 0.119 5.061 ± 0.120 2.910 ± 0.330 1.560 ± 0.019

**Shoot** 0.189 ± 0.049 0.215 ± 0.006 0.264 ± 0.053 0.240 ± 0.012 0.129 ± 0.096 0.139 ± 0.001

**Dry weight (g)**

**Root** 0.047 ± 0.018 0.053 ± 0.024 0.065 ± 0.027 0.060 ± 0.038 0.048 ± 0.039 0.033 ± 0.001

**Whole plant**

0.237 ± 0.021

0.269 ± 0.013

0.330 ± 0.016

0.300 ± 0.025

0.177 ± 0.019

0.173 ± 0.002


#### **Table 7.**

*Antifungal activity of bacteria isolated from SMS in dual culture plate assay.*

**Figure 1.**

*Antifungal activity of bacteria isolated from SMS in dual culture plate assay. F1 -* Fusarium *sp. F2 -* Alternaria *sp. F3 -* Phytophthora *sp. F4 -* Aspergillus *sp.*

#### **4.3 Isolation of microbial flora from SMS**

In this study, four different bacteria were isolated from the fresh spent mushroom substrate after *Pleurotus* spp., cultivation. The colony morphological variations among the four bacterial isolates of the bacterial strain 1 (B1) were irregular in shape with a colony size of 1.2 cm dia. The colonies had eros type margin rough or dry texture and were white in color. Cells of bacterial isolate B2 showed a diameter of 0.7 cm. The margin of B2 colonies were entire with smooth texture, mucoid consistency and cream in color. Colony morphology of B3 isolate showed irregular shaped colonies of 0.5 cm dia. B3 isolate colonies showed serrated margin with smooth or glistening texture and cream color. The B4 bacterial isolate had circular shaped colonies of size 0.2 cm with entire margin and yellow in color. The cellular morphology of B1, B2 and B3 isolates was observed as rods while B4 isolate had short rod shaped cells.

The biochemical properties of four bacterial strains isolated from the SMS obtained after *P. eous* cultivation showed significant variations in the biochemical characteristics studied. Based on the observations and results obtained by subjecting the bacterial colonies in different identification techniques, bacterial isolate B1 was identified as *Bacillus* sp., isolate B2 was identified as *Clostridium* sp., isolate B3 as *Pseudomonas* sp. and B4 as *Escherichia coli*. The findings on antifungal activity of four bacterial strains isolated from SMS are shown in **Table 7** and **Figure 1**.

**259**

*Screening and Potential Uses of Contaminated Spent Mushroom (*Pleurotus *spp.)*

Mushroom growing is an ecofriendly activity as it utilizes the waste from agriculture, horticulture, poultry, brewery etc. for its cultivation. However, piling up of "spent mushroom substrate" released after mushroom crop harvesting may cause various environmental problems, including ground water contamination and

Production of 1 kg of mushrooms will generate 5 kg of spent residual material called spent mushroom substrate (SMS). An average farm discards about 24 t of SMS per month [37]. In Ireland, approximately 254,000 t of SMS is generated each year [38] and in The Netherlands, more than 800,000 t of SMS is produced per

In some countries, waste management of SMS is a major problem faced by farmers. Apparently, the obvious solution is to increase the demand for SMS through exploration of new applications for utilization. It would be more economical and favorable if SMS is to be recycled and reused. Considering the high organic matter of SMS, rapid advances have been made and the number of

Potting medium is an important factor for the production of crop in containers,

Ability to provide essential nutrients to plants is one of the most fundamental criteria while judging the suitability of a growth medium [41]. Primary nutrients like nitrogen, phosphorus, and potassium are more available at pH 5.5–6.5 for substrates of organic and mineral origins [42]. Moreover, with the increasing pH, the solubility of many nutrients is reduced and some nutrients are precipitated as solid materials that plant cannot use [43]. In contrast many researchers reported high salinity of SMS, which is mostly responsible for the limited use of SMS as a

Results of our study showed that SMS had 0.87% nitrogen, 0.26% phosphorus content, 0.19% of potassium. SMS has been shown to increase the nutrient availability of growth media [44]. In general, most mushroom substrates have low N content, typically in the 1% to 3% range [45]. The overall nutrients of SMS were not enough to support normal plant growth without external fertilizer application. It is well known that physical properties of soil were directly related to crop yield [46]. SMS by maintaining high organic matter content in the soil and by providing the three primary nutrients e.g. nitrogen, phosphorus and potassium helps to provide

Growth of root and shoot weight of the seedlings of green gram, black gram, tomato and chili were significantly higher when grown in 60% SMS mended soil than the control (**Tables 3**–**6**). Higher nutrient availability provided by SMS might have contributed to the better growth in 60% amended soil. Spent mushroom

and component and properties of the potting media are very crucial for higher and quality yields of potted plants. Chemical properties of growth media are very crucial from the point of view of nutrient availability to the plants. SMS used in our study in **Tables 1** and **2** showed that pH range 6.10 and EC range 1.75 dsm−1 are suitable for normal growth of plant. The average moisture content of SMS in our

scientific research has increased in the past few years.

**5.1 Composition of spent mushroom substrate (SMS)**

study has been measured as 72% which was also reported. [40].

**5.2 Effect of SMS on growth and biomass of selected plants**

*DOI: http://dx.doi.org/10.5772/intechopen.93863*

**5. Discussion**

nuisance [20, 36].

potting media [9].

soil fertility [41, 47].

year [39].

*Screening and Potential Uses of Contaminated Spent Mushroom (*Pleurotus *spp.) DOI: http://dx.doi.org/10.5772/intechopen.93863*
